long but advice needed

I have an issues and me and my daughters father have been together this whole time I'm 8 months pregnant and decided to look through his phone found out he was snap chatting his ex and he tried lying I was hurt like what why how I'm pregnant well that wasn't all she blocked me off everything refused to talk to me and told him "told you I didn't want drama now leave me alone" she did know about me being pregnant me and her were friends in the past and this isn't the first time she's done this. At this point I was broken then her "friend" texts me off her number obviously I'm unblocked now and tells me how my boyfriend/daughters  dad has been hitting her up constantly asking her to go over and saying he wanted to be with her and calling her a lot I am completely just shattered I guess because my dumbass didn't think he would do this especially me being 8 months pregnant. I completely blocked him haven't talked to him and now I just don't know what to do . About the birth. My daughters  last name how everything will be because I can't keep him blocked forever. I just need advice. I felt played this whole time and to top it off she said he invited her to make tamales last weekend which crushed me more because hello I'm pretty cool with his family how can he just invite another girl over? She told me she denied hanging out with him every time he asks and always "defended" me which I don't get like why not tell me why talk to him knowing I'm with him and pregnant and she has a daughter too. I need advice because I need to eventually soon be a big girl try putting my rage aside and figure out my plan. I don't want to keep him away from her because I'm upset or hurt that's not right. I just truly don't know what to do.