My ex is happy and it hurts

When I was in high school I dated this guy who sexually assaulted me and told me and made me feel like it was all my fault. I am now in a healthy and loving relationship and feel safe. But I was going through my instagram followers and found his step mom ( I didn’t know she followed me). The last picture she posted was of this girl, my ex and her and her husband. The post said you have no idea how excited we are. My exes parents were wearing shirts that said grandma and grandpa. Although I’m finally happy I still think about all the crap he put me through every day. It hurts to see him happy, in love and now having a kid. In my head he doesn’t deserve this. He gets to move on and I have to carry all he has done to me. I don’t know how to feel but I’m upset and angry and the feelings he made me feel are all rushing back.