1. It’s her problem, not yours. If she is jealous of you, that will be causing her great pain. Easy for me to say, but try to think compassionately towards her. She must be very insecure.

2/3. I had a similar issue when I reacted to someone that was upsetting me, but my husband didn’t support me. It turned out that he was so firm in his belief that I was a much “bigger” person than this other, he couldn’t take the notion that I was upset seriously. Maybe it’s the same for your husband and MIL. They think “That’s just , her opinions/comments are not important” (as if she were a child, perhaps?) This would explain why your husband thinks you need more confidence (to be secure in your place in the family hierarchy as “above” her) and why the MIL is reacting defensively in calling you jealous (babies must be protected!)

4/ I’m so sorry that you’re in pain Focus on yourself and take an emotional step back from cousin as much as possible. When your situation improves, I suspect her comments will mean a lot less to you. They just hurt more now because you’ve taken so many knocks. Maybe keep a diary of “coulda-saids” – all the witty, sarcastic and abusive things you COULD say in response to her provokations, but choose not to, because you’re the better person 🙂