I am so grateful I get along with my in-laws. DW had it a bit rougher with my mother at first, but once the roles and expectations were ironed out, things got much better.
I don't know if you're looking for any advice,
@Jacinle, but you posted this in "ask a mustachian," so here are a few thoughts:
1) Don't let your in-laws' inappropriate behavior occupy your thoughts any more than you absolutely have to. Stewing over it, holding resentment, ranting, etc will only rob you of happiness, especially if those thoughts continue after the in-laws have left.
2) Recognize that you cannot force change in others. You can encourage change overtly, or manage the situation in order to encourage it, but you can't force it. Recognize what is in your control and what is not.
3) This one is hard: choose not to be offended. I've heard it said that "He who takes offense when none is intended is a fool, and he who takes offense when it
is intended is a
great fool." If the in-laws don't mean offense, there's little sense in being offended. If they *do* mean to offend you, then being offended only hands them power over you.
4) IIRC, there are some cultural expectations or traditions driving some of this behavior. A guy I knew a long time ago had this nugget of wisdom: "tradition has no claim on sanctity." If a particular tradition is making life harder, get rid of it. This can also be hard, because humans are creatures of habit, and things that deviate from the norm are typically viewed with suspicion or hostility.
5) You need to sit down with DH and set some boundaries and expectations. Boundaries in terms of your in-laws' behavior (e.g. "they are welcome to stay up to three nights"), but also DH's behavior (e.g. "if MIL disparages my parenting, I expect you to stand up for me"). Also, expectations for how you will act in certain situations, so that nobody is surprised ("I'm willing to be social with the in-laws for up to two hours per day, if the schedule permits." or "If MIL starts criticizing me, I will leave the room". Then enforce those boundaries ("because MIL did X, Y, and Z, we will decline their next visit, and explain that their behavior made our family miserable for three weeks, and we are not interested in repeating that experience.")
The biggest thing for me, though, is #3. Don't sweat the small stuff, and it's mostly small stuff. The snide remarks, the implied (or inferred!) put-downs, the exclusionary behavior...don't let it be about you. Let the in-laws try to make themselves feel better by putting you down, if indeed that's what they're trying to do. The best revenge is a life well-lived, and you have the power to achieve exactly that.