Just need to vent..

I had a bestfriend since 1st grade. I am 21 and he is 22. We lost connection for a few years and reconnected in 6th grade. We clicked so fast like we never lost connection.. we were always so comfortable with each other and felt like brother and sister. He had a big crush on me and we dated a few times and it never worked out because I felt like he was more of a brother to me. We worked it out and just stayed really really close friends. We always told each other everything and we were so close. He knew my fiancé and I met his girlfriend like once. Although his girlfriend is the very jealous type. I never had a problem with her and I REALLY wanted us to get alone so we could all hangout and be friends. My fiancé was cool with him so why couldn’t she be ok with me? Well I became pregnant and I’m due next week & his girlfriend got pregnant around the same time as me.. we are both having boys and it was so exciting that he wanted our sons to be friends and I was happy with that. Then his gf got angry and jealous saying that he’s cheating on her with me WHEN IT NEVER HAPPENED. We barley talked all the time cause we are grown up and have lives we only talked here and there. I would never hurt him or his relationship ESPECIALLY my relationship because I am extremely happy. Anyways he told me we can’t be friends and she was trying to kick him out cause she didn’t believe him.. anyways we aren’t friends now and they are good which I’m glad because they need to work it out or especially he has to be there for his son.. but everyday it still gets to me because now I lost my bestfriend over this girl which I understand mainly because now he has a son he has to think about and the mothers usually always gets the rights and she is the type to take the son away if anything happened so I totally get it. But I was really looking forward for our boys to be friends.. even my fiancé was excited. It just really really sucks. All the time I want to message her and have a genuine talk with her but I don’t want to ruin them or him being taken from his son if she ends up getting all pissed off.. I definitely think she is toxic for him but I never said anything bad about her to him or in general. I want him happy and he’s excited so I don’t want to ruin anything. I’m just upset and needed to vent