I need to talk to someone 😢

My partner and I have been in a relationship for 4 years and we have a 6 month old baby together. Lots of things have been building up in our relationship, arguments, I feel he ain't interested anymore, don't think it helps that we can't have sex as my vagina got really damaged at birth. But for the last few weeks I've been imagining my life without him, I feel happy when I think about it, I don't know if I'm staying with him because of my baby or if I'm just being stupid thinking I don't want to be with him, I'm dealing with postpartum depression and I don't know if it's to do with that, why I'm feeling this way. I'm just so unhappy in my relationship, he hasn't done anything wrong but we just argue all the time and he doesn't show affection towards me or even listens to me when I talk, I feel as if he's my child the way I talk to him. We had a very bad relationship before I was pregnant, emotional and physical abuse from his side. But when I fell pregnant he is now a changed man, I tried to leave him so many times but he would threaten me years ago. I think the reason I want to leave now is because I know I can without being hurt off him, Can someone offer me some advice, it's like the words keep reaching the tip of my tongue and I'm going to tell him how I feel and then they dissapear again😩 I don't know what to do!!!