Annoyed or overreacting

I need help. Long story short. My sister cheated on her husband. She claims he would hit her but we never saw him actually hit her or see signs that she was hurt. After this cheating happened the got back together for a couple of months and out of the blue according to her he just left one day after work. We were all shocked but none the less stood by her and helped her out but that didn’t last long after a month of him leaving she already had an other guy moved in with her and this is where she started to claim that her husband was abusive to her and their daughters and a restraining order was placed and well her and the other guy didn’t work out it only lasted about 2 month and she kicked him out and went back to her husband when she was going to take off the restraining she claimed that she couldn’t and it had to stay for a year after courts and everything we were told that they could be together as long as their daughters were present (I’m not sure that’s true) well one thing lead to an other and she ended up pregnant from her husband but at the same time she was talking to a guy from Texas and a few weeks ago she started helping my dad move some extremely heavy box and ended up losing the baby and she claimed she didn’t know she waS pregnant but before the miscarriage she kept saying things about thinking she was. Well she lost the baby about 3 weeks ago but just 2 weeks ago became the girlfriend to guy from Texas she was talking to. I’m so tired of being lied to and being used. I can’t stand her I feel hate for her and angry that she didn’t care about her baby and all she cared about was to be this guys girlfriend and maybe it’s just cus my husband and I have been trying to get pregnant for 5 years and haven’t been able to I’ve always defended her in the past but Ive had enough of her. Am I really over reacting or do I have reason to feel all of this. I’ve tried to act like everything is normal and nothing has happened but when I see her and remember everything all I want is to shake her and put some sense back into her . It’s getting to the point where this is the only thing I want to talk about and it’s constantly on mine mind and all I want to do is talk bad about her