Throwaway account because reasons. Some details vague or changed and all names and locations changed for privacy/other reasons.
Short version: My sister-in-law (We'll call her Karen) is juggling two guys (We'll call them Mike and Rob), lying to both, and lying to my wife (we'll call her Mandy) and I. I have no idea how to proceed, or really how to handle it.
Long version:
Karen and Mike go way back. They've been dating since about 2010. At the time, Karen didn't break up with her previous boyfriend when she met Mike. She dragged it out for a little while (sometime between a few weeks and a few months) until he figured it out. Not exactly shining integrity, but she was in her late teens at the time. Anyway, Karen and Mike were by all accounts very happy together, moved in together, and eventually in with Mandy and I, sharing a big house (rental) by 2012.
Everything was going great at this point, Mandy and I got to know Mike very well, and very much considered him "part of the family." He's a really awesome guy, and I (as a straight dude) would definitely consider him "hubby material." We all pretty much consider each other family.
Karen bought a new car in late 2013, financed in a five year note.
Mid-2014 or so, things started changing a bit. Karen had always been a gamer, and picked up a habit of a certain online MMO game. She would play it for many hours at a time. She had a headset with a microphone, which is very common for people who play such games. But we noticed that she would act differently on the mic when Mike wasn't around. She'd act a bit flirty, or swear in a cutesey way. She eventually joined a guild in the game that was mostly people in Germany. She used this as her reasoning for then sleeping odd hours.
Right around this time, Karen moved her computer from the living room into Karen and Mike's bedroom. At this point, we heard from her very little, she slept very odd hours, and she only left that room to go to work or get fast food. We knew there was some particular guy she'd talk to in her game often, but she shrugged it off and said he was just "some loser" that she was "using" to get free stuff in the game. (It's no secret that some guys in online games will do that for any girl they see, so it penciled out.) We figured out that his name was Rob. To us it just seemed like she was sucked into the game. This went on for about a year.
March 2015, Mike went on a vacation to Japan. He wanted to take Karen with her, but she didn't want to go (his brother went with him instead).
Then Mandy and I bought a house (mid-2015) and the fellowship broke. We moved into the house we bought, and Karen and Mike moved into a "crappy" apartment. Karen was not shy about how much she hated the apartment, but it was what made the most sense for them geographically and financially. Things pretty much continued as they had at this point, but she couldn't "hole up" in the bedroom with the game anymore, as there wasn't space.
Throughout this time we saw way more of Mike than Karen, and Mandy considered Mike more her brother than Karen her sister.
In August 2015, Karen and Mike told us that she was going on a trip to Belgium. Mike seemed excited for her, still high on his earlier-that-year international travel. She quit her job, bought a one-way ticket without a return flight, and said she was staying with "some friends from her game." Since this point, she hasn't has a job or worked at all.
After a month, Mike started asking her when she was coming back. She gave excuses and put it off. Eventually she came back one day before her tourist visa would have expired (gone for 89 days). She seemed "normal" after getting back.
May 2016, she left for Germany claiming she was visiting for a few weeks. Excuse after excuse later, she came back in August after 78 days.
Just over a month later, she disappeared in the middle of the day, and when Mike got home from work and called her asking her where she was, she said she was at the airport, going back to Germany. She gave a generic lame excuse as to why she was going. Supposedly going to be gone for a "week or two." This was where Mandy and I really knew something was up.
In January 2017 (Karen still in Germany), Mike shows us "weird texts" he got from Karen. It's someone using her phone claiming to be "her boyfriend Rob" that wants know what's "going on" between Mike and Karen. Rob says something about them wanting to get married.
Karen spins it as a crazy guy hacking her phone and a bunch of other baloney. Mike falls for it and sympathizes. Our suspicions increase. We try to push Mike in that direction saying things like "I don't know if one of us could deal with the other doing something like that." But he just turns it into some I'm-so-great quality and says that he just has more patience. (We'd call it denial.)
At that point, Mike is so worried about her perceived danger from this "crazy guy" and can barely can sleep each night. He's working full time at this point, paying his bills and hers (including her car note and insurance), and going to school full time. Stressed out of his mind. He keeps pleading with her to come home, and she keeps finding reasons not to be able to. From generic "I'm sick" to "I lost my passport and need to get a new one" to all kinds of nonsense.
Mike finishes his semester and graduates with his degree. Somehow, he got straight A's that last semester (he's "a trooper") and didn't accumulate any extra debt from floating Karen's expenses and paying for school incidentals (and working his ass off). He estimated that her being gone cost him about five grand altogether.
Mike lands an internship 1000 miles away near where his parents and brothers live. He moves there in May (still in the country), ending their lease in the "crappy" apartment.
Two weeks later, Karen finally comes home (after 275 days in Germany). Mike bought her a ticket, and she flew to where Mandy and I live, ostensibly to say hi to us, stay with us for a week or so, and then fly to where Mike moved to. That didn't happen.
I picked her up from the airport. Things seemed "normal" and "like the old days" as we talked on the way home. Mandy was out of town until two days after Karen got here. Karen and I talked, some about the "crazy guy" Rob that had allegedly stalked her etc.
When Mandy finally got back and saw her, she quietly told me that she was 99% sure Karen was pregnant. I thought she was right, but didn't notice before she said anything, because I'm just a dumb guy who doesn't notice things.
A few days later, Karen took our car ostensibly to go to Urgentcare since she had kidney pain and wasn't sure what was causing it. A few hours later, we got a terse text from her saying it was something bad and she had to see a different doctor. We're convinced she's getting an abortion, and that it's Rob's.
A few hours after that (while Mandy and I were eating dinner), she calls me in tears saying that she's in the ER and she has a mass in her stomach that might be cancer. ...not what we were expecting.
We go see her in the ER, she'd going to get an MRI and everything, turns out she has a giant ovarian cyst. She's transferred to another hospital and a couple days later she gets surgery to have it removed, along with one ovary. Surgery goes well, she couldn't move or walk for a few days in the hospital afterwards but eventually she's discharged. She said the cyst weighed 30lbs, and she definitely lost the "pregnant" look. We assume this is all true and that wasn't pregnant (but suspect that she thought she was).
We brought Karen home, and helped her during her recovery any way we could. She's been recovering quickly, and been able to walk around the house again.
About a week ago we realize she's been watching our mail like a hawk (she put our address down for everything), which is not her style. This gave away that she was hiding something medically that she was going to get a bill for.
I signed up for USPS Informed Delivery, but everything that's come so far has had an explanation.
I logged into her Ting account (that I helped her make a few weeks ago when setting up a new American phone for her), and checked her call history. The morning she ended up in the ER, she called some medical clinic, then shortly afterwards some pregnancy resource from the county, and then Planned Parenthood. To us, this confirmed that she definitely thought she was pregnant (like we thought before).
And then yesterday I found irrefutable proof of everything we've suspected, and worse.
Through some less-than-kosher methods, I obtained the password to one of her email accounts (the fact that she has so f-ing many email account is its own red flag, but anyway...).
She has a boatload of damning emails in there. She's definitely in a serious relationship with Rob.
The first, and most disturbing is a fake conversation between her and Mandy from just before she left Germany. She made a separate fake email account for Mandy and used it to write a fake conversation. The conversation implied Mandy knows all about Rob. She told "Mandy" that she was 8 weeks pregnant. "Mandy" gave her a few key (incorrect) details. First, she said that Mike not only moved but has a new girlfriend (he totally doesn't and is still 100% in love with Karen) to quell jealousy from Rob. Then she said she'd be home to pick up Karen (she wasn't, I was), also to quell any jealousy concerns. Third, she said that Mandy was buying the ticket, not Mike, because that obviously wouldn't fit her narrative she's spun to Rob.
Then she had another email written to herself, but really to Rob. She was telling him that Mandy bought her a ticket to "visit" America, since she was afraid of the abortion cost in Germany, and since they were planning on getting married and getting a house, that it would be her last time for a while to be able to visit family. She went on to say that she knew he was afraid "of [her] cheating on [him] again" and mentioning the lie about Mike having a new girlfriend.
We're assuming she left that email open for him on the computer when she left, then left behind the fake conversation with "Mandy" in her inbox to corroborate what she was saying and quell any jealousy/"cheating" concerns.
Then there were a few emails since she left Germany that basically establish the following happened while staying with us:
She was pregnant, went in to PP for an ultrasound, and they told her about the then-unidentified cyst.
She went to the ER, they eventually told her it was a cyst, and that the fetus had no heartbeat.
When the cyst was removed, they also removed the fetus.
Grotesquely, the cyst provided a nice "cover" for her pregnancy/etc.
She's lied to everyone, all around. It's pretty fucked up. All she had to do was break up with Mike, and she would have been free to tell the truth to everyone else about everything. We could have been happy for her. But she didn't.
Since we now have irrefutable proof of everything, we could tell Mike, which would destroy him. All he did during the last 275 days she was gone was worry every night, and to learn that was all a lie would be devastating. I'd probably fly down and take him out for a couple beers.
We could also tell Rob, since he deserves to know too. He'd probably crater too, and she would not be welcome back in Germany.
Telling both would pretty much destroy any chance Karen has at a future that looks anything at all at what she had planned. We have no idea what she had planned, or what her true endgame with all this was (on some perverse level, it almost seems like she wants a "backup" to either guy).
If we tell both Mike and Rob, and they both accordingly turn their backs on her (as they should, truly), she'll have no where to go but stay with us for the short-to-medium term. And while that would be logistically less-than-ideal for us, it would kick her even harder. She's still my sister-in-law and she's still Mandy's older sister. We've been taking care of her since her surgery since that's what you do for family.
We have no idea what to do, as every option seems "wrong" on some level. We can't keep quiet, and we can't tell them without destroying my sister-in-law's life. We love her as family even if she's done some pretty fucked up stuff.
What the hell is "the right thing" to do?
Thanks for anyone with the patience to actually read all this. I know it sounds like a fucking soap opera story.