A whole mess

So last year my fiance and I had his friend over quite a bit. He was always drunk and got aggressive (grabbing people's butts even when they said to stop) a few times. Well one day last December he needed to do laundry and he did it at our place often so he came over. My fiance was going to drive his brothers family home and I didn't want to go on a two hr drive so I stayed home. I went in the kitchen for a snack or something I don't even remember what now but the "friend" came up behind me and started rubbing up on me. I said to stop. But then he starts rubbing my lower back. I move but he follows. He pushes me up against the counter and has sex with me. I didn't think about it as rape for a long time, I was just uncomfortable and didn't stay around the guy anymore. I have a ton of guilt for not fighting back more. I feel like I handled it in the worst way. I'd been abused before and I got scared he would hurt me or tell my fiance I cheated if I tried to protect myself. It was like I just fucking froze. I was so scared that my fiance would hate me for it happening that I didn't tell him for months. I've told him at this point and it pretty much shattered our entire relationship. He went on a drug binge right after finding out and now drinks almost every day. He talks about just leaving town. I really miss being able to talk to him like my best friend. I'm in a bad spot mentally and this is pushing my limits. I've had a history of childhood abuse, depression, and anxiety. Now I am struggling with postpartum depression as well. I think I was so scared of losing what we had that I lost what we had. I don't know if we will be able to get back together and I blame myself.