This is interesting. I'm close to the husband of a couple in the same situation. If you're located in the Hampton Roads area of Virginia, we could potentially be talking about the same couple. Feel free to PM me if that's the case.
My boyfriend's son is separated from his wife. They have a two year lease with something like a year and a half left on it. My boyfriend's son moved out -- to my house, where my boyfriend and I live. His wife is underemployed and I doubt she could cover the rent, unless her parents help her. Her unwillingness to get more work has been a sticking point with them. She wants a job she considers suitable, but until she finds one, he wanted her to at least get something to bring in some money instead of mostly sitting around waiting to get pregnant and obviate the need to ever have a job. I think he's paid a couple months of rent since he left, because he's used to taking care of her and didn't want to be mean by abruptly ending his support of her. But recently he let her know that would be ending. He is a full time student, so his income is minimal.
He wants to make sure the landlord gets paid, and doesn't want to break the lease. In fact, he's like to move back into their rental, but of course she has to be gone first. Her family is only a couple hours away and her parents already support one of her twentysomething brothers who also can't quite bring himself to be independent. So she has a soft landing place. He says he told the landlord that if she can't make the rent and leaves the place, he'd make up back rent when he moves back in. But he won't pay rent on a place he's not occupying. That would set the wrong precedent anyway. They're getting divorced, although she doesn't want to, so she'll have to support herself or go home to her parents. They weren't married long and there are no children. Obviously that's not the only reason they're splitting up, but the other reasons aren't relevant to this thread.
I think he was smart to propose this deal to the landlord, because the landlord knows he'll get paid. Hopefully he doesn't have to evict her. If she can't pay the rent, hopefully she will either go to her parents' place or find something else she can afford on her own. It's always sad when people split up, especially when all involved are good people. But when they do, each person has to be independent, eventually, at least for a short marriage with no kids. It sucks that the landlord, who has done nothing wrong, is in that position. But in this case he has reason to believe he'll be paid the rent, even if it's not on time. Hopefully he will not see the need to involve lawyers. Maybe you and your tenants could make a deal too. I would bet that would be better for you and for them.