My (30F) fiance (33M) wants me to stop talking to my sister because her husband put him in the hospital

I tried posting this in AITA, but I missed their rule about no violence. I hope I can post this here. I really need all the guidance I can get.

My fiance and I have been together for 2 years.

Over Thanksgiving weekend, my fiance and my sister's husband bickered. A lot. Most of it was snide comments made under each other's breath. My fiance got fed up that weekend and made some offensive comments. My sister's husband (24M) reacted physically. Badly. My fiance ended up in the hospital (he's okay, but he has a broken nose, broken collar bone, and bruising). My sister's husband is currently sitting in jail on felony assault charges.

It's an ugly horrible situation all around, and I'm by no means excusing my brother in law's behavior, but I've been in almost constant contact with my sister over the past week over the situation. I feel horrible for her. She's my baby sister (24F), and her husband's been dealing with some MAJOR mental health issues the past few years, with this incident really being the icing on the cake. She's, of course, really upset with him and is thinking about divorce.

My fiance thinks I'm being a bad partner for still talking to her since her husband hurt him so badly. He thinks we should cut them both off (her husband was also banned from my mom's house last weekend where it happened because of this). My sister's apologized as much as she can, but she can't force her husband to apologize, which is what my fiance wants to happen (although she's told me her husband is apologetic he just hasn't apologized personally because he's in JAIL and there's a no contact order). I'm not about to forgive her husband, I understand my fiance wants nothing to do with him and I respect that. However, my sister is still my sister and she's not at fault for her husband's doings.

TL;DR: My sister's husband beat up my fiance over comments my fiance made. My fiance wants me to stop contact with my sister.

Should I stop talking to my sister until the legal situation has calmed down? How can I best explain to my fiance that my sister is my sister, I care for her, I'm worried about her, and I don't want to abandon her during this just because her husband was out of line. This has caused a lot of arguments between me and my fiance in the past week. I don't want us to break up over this but I'm worried it's headed there since we can't agree on how to proceed.

Submitted December 08, 2019 at 12:07PM by ThrowAwayForMe10928 https://ift.tt/354mNkH