Are my feelings justified???

My big sister (and only sister) is the only sibling I’ve had a relationship with. When she married her husband she moved states and stopped talking to me. I was devastated. 4 years go by and they move back and she still barely talked to me, and then they split up. He was extremely mentally abusive, told her she was ugly made foul comments about her lady parts. Locked her in a room when his friends were over etc. then he had multiple affairs one being her underage sister (on her dads side). She blamed her little sister and just went back to him today. She has been “living” in my fiancé’s house for almost a year was behind in rent over 1k but that was fine as long as she was away from him. She’s moving back in with him this weekend and she’s my maid of honor and she’s back to not talking to me. My mom thinks it’s good they are back together and my dad yelled at me for having any anger towards her. I’m partly angry because while she was at my fiancé’s house she was in a relationship with his cousin and he fell hard for her and she played him (I don’t think intentionally). So now he’s heart broken and I’m back to not having my sister. She’s been ignoring the bridesmaid group chat and even my texts about the wedding.... am I wrong for being hurt and mad?