Malcat, you've given a lot of really, really excellent advice in this thread. Super insightful and helpful. I agree that the "ideal outcome" is self healing. However, I think there is also room here for OP to work with spouse to gain spouse's support to help MIL moderate some of her behavior. The fact that MIL's rude behavior is bothering OP is IMPORTANT, and both spouse and MIL should CARE how OP feels, even if they think OP is silly or too sensitive, and actually make an effort to behave in a way that makes OP more comfortable!
Peace in the home is really important. If you consistently disrupt peace in my home, then I will try to help you understand and stop. If you refuse to help me feel peace in my own home, then I will either kick you out or I will leave myself. That's how I roll. Extreme? Yes. Highly effective? Also yes. It's a high stakes game, though, so this is a technique to use sparingly. OP may not be ready for that level of extreme response, which ideally only happens after a lot of communication hasn't been working.
But it's not just a case of "OP needs to learn how to cope" that I am reading in some responses. Yes, OP can work on coping strategies, as we all should when we are being annoyed. But I also think it's really important for OP to keep communicating calmly to spouse that feelings are hurt due to both thoughtlessness on spouse's/in-law family's part. Their blaming of OP for being too sensitive, rather than recognizing that some of MIL's behavior is truly obnoxious, is a big problem. As some have pointed out, IT IS SPOUSE's job to stick up proactively for OP and communicate with spouse's side family.
Instructing an adult how to properly hang up their own underwear to dry is one of the most obnoxious things I've ever read. Seriously. That's just plain rude by MIL. Whether she means to be rude or not, she is being rude. Spouse can certainly learn to say to MIL "please stop instructing OP on how you think people should do household chores. Please stop redoing work OP has already done. I love you, Mom, but I like OP's way of keeping our home, Mom, and this is
our home." If spouse is too spineless to have that conversation with MIL, giving her specific examples so she understands, then that is indeed a problem that spouse needs to work on. If you live in your inlaw's home . . . then this is much more difficult (I am not sure your living situation.)
Would you put together a dinner that you knew one of your family would have nothing to eat?
When you decided to order a takeaway would you order something for everyone, even when that someone is not present, and unaware of that you are ordering?
If you are bringing a treat home, would you bring it for everyone?
This actually comes up in my on-the-go blended family a lot, and I ALWAYS call or text to see if the other people want any food, what they want, etc. If I can't get in touch, then I just buy at least one thing I KNOW that the person not with us likes and bring it home with me to tell them I got it for them. A full meal if it is meal time and I have no reason to think they have other meal plans. If weird time or I think they have other plans, then I still often get something small just for them like an appetizer, side dish, or dessert if I think they may not really need the food.
Sometimes they are happy to eat it right then, and sometimes they don't want it right away, but my effort is not wasted anyway. Always they are happy I thought of them. I will not change that because it is more important to me that the other person knows I am thinking about them and it doesn't matter whether or not they really need the food right then. The only time I mess up is when I *think* they had other meal plans for a full meal and I am incorrect (or their plans changed.) Then I apologize, because saying "I'm sorry I didn't know to bring you something! Next time I will do better!" is much better than just saying "Here is our leftovers that you don't like . . . tough luck for you."
I hope you were able to tell your spouse that it bothered you when they came home with only leftovers that spouse knows you do not like, and that you hope they will think of you next time and actually order something you want to eat "to go" and bring it home, even if you will be reheating it later. If you didn't feel ready to communicate that at the time you were hurt, then you can still bring it up at a calm time over a cup of tea.
Especially with you being the only income earner, they should
really be going out of their way to make sure the food/chores etc. are completed in a way that helps you relax at home. Please keep that communication open with spouse.