I’m going to ramble. Forgive me. I mean to be helpful.
The first thing that comes to mind is a tenet from The Four Agreements—that people endure exactly the amount of abuse they think they deserve. On some level, you are accepting these efforts to degrade you as real—as carrying real weight. There are probably other people in your life who, if they uttered the same comments or behaved similarly, would elicit little to no antagonism from you because their opinions carry little weight. So, if the evaluation of you feels true or false depending upon who it comes from, is it objectively true and does it deserve your antagonism?
Second, you are dealing with people who are acting small. Your husband is disapproving of your efforts because it makes him feel like he’s an expert at something, when in reality, he’s probably a weak person. Maybe you and your capabilities make him feel weak or threatened. So he likely has to demean your efforts to preserve his ego.
That he complains to his sister shows that his family (still) has influence over him. Guessing that there’s some degree of dysfunction in his family, he still hasn’t come to realize it for what it is and the sway that it has over him. Hypothetically, would he complain to you about his sister’s behavior, or is it taboo to surface that kind of discussion? Does he rationalize her behavior? If I’m on the right track, these are big blinders for him. He doesn’t get that his family’s influence isn’t helpful for your relationship. He could have shut up about it to his sister and talked to you directly, or at least been protective of you. The problem is he doesn’t get it, because he is still playing the role of brother and not husband.
Similarly, your sister-in-law is too caught up in showing you up and being protective or maybe even controlling of your husband. It’s pathetic behavior, really. How sad that she thinks and feels like this is the best way to respond? How lacking in imagination, compassion, thoughtfulness, kindness? What lack is she compensating for? How childish, catty and small?
If I were you, I would start picking battles. The key, though, is that you have to come from a position of strength. You have to see and feel that you are doing your best, you are acting like a reasonable person, you are being thoughtful, kind and sane. This can be difficult to see when everyone around you is invalidating you. If you believe their words, you are lost, because you cannot tap into your inner strength.
You have to understand that they are acting out, and that their behavior has less to do with you personally than their own insecurities, blind spots, and emotional handicaps. You have to love yourself and love the person opposite you, but not feed or reward the behavior, and you have to be consistent about that. You have to learn how to stop accepting the abuse. That can be a difficult thing to accomplish, because it asks you to approach the line towards being a bit of a jerk yourself, but really you are just being a sane person in a storm of insanity. And, it can be difficult to fine tune a response that isn’t about over- or under-reacting, but just not accepting crazymaking behavior.
I rely on two tactics to thwart such behavior. I put that person in time out, meaning I don’t entertain that person until they’ve come to their senses, or I give the behavior back.
By putting them in time out, I’m not rewarding or feeding the behavior. I acknowledge to myself that they’re crossing a boundary, and it’s not healthy for me to continue interacting with them. I don’t hold a grudge about the behavior or the person—if they decide to act like a normal human, I’m happy to pick up the conversation, but while they are acting badly, I don’t give them my attention.
By giving the behavior back, I’m immediately freed of those feelings of stewing over getting stung. I don’t have to deal with feeling bad, like you are doing now. They can have their own medicine back. I don’t care. I’m not accepting their abuse, so they’ll have to find somewhere else to put it or hopefully figure out that their behavior is dumb and unhealthy.
If you’re really strong, you can just pity them in the moment. See their weakness and feel compassion for them. Again, how sad that they believe this is the most relevant way to behave? How lacking in imagination?
They use you to preserve their egos because it works. If you ceased to be food for them, then their relationship with you absolutely will have to change over time. Stop giving a fuck about their criticism. Ask them why they don’t think to participate differently. Point out to them how they’re not growing as human beings. Do it compassionately if you can, but first do it to maintain your boundaries.
Also, take a long view. Assuming you aren’t going to bail on this situation, resolve to have a somewhat lengthy period of fucked up interactions. They will need time to figure out that their crap behavior isn’t going to work on you anymore. Wreck a holiday now, so that next year they’ll think twice (or maybe even once) before pulling this kind of BS. Call their bluff and dare them to make it worse. You’ll take a chance that your relationship will fall apart, but one thing for sure is that you’ll never have to suck on these feelings again, and you’ll never again ask this question.