Struggling with relationship

So I’m gonna start from the beginning please no judgment…. I met my now fiancé through who is now her soon to be ex husband… they were together at the time we met and he gave us permission to sleep together long story short he treated her like crap and she and I became attached to each other quickly and she ended up leaving him to be with me… after about a week or two of us being together she cheated on me with him and would make up every excuse she’d then go on to move back in with him and then go back and forth between us up until this December when she finally left him.. they have a child together and he would use the kid against her and everything else in the past and hurt himself to make her come back… I kept forgiving and took her back each time… she since December has shown me a different side of her she said she was done she showed me differently.. not even 2 weeks ago he started on his normal behavior once he seen she was back on fb and started making fb posts and they went back and forth posting stupid things and he thinks she wants him back now and she says she doesn’t but she refuses to block him on fb… we have many court hearing dealing with the child’s father because she’s wanting primary custody and wants to get a divorce she says but part of me I guess is still bothered she refuses to block him on fb because of the fact he has no reason to be able to see her stuff and all he causes is drama. She told me tonight that I was controlling for asking for communication with her and I and to block him for peace of mind… I just idk what to do she tells me we can make it through anything together and all but I just repeat myself with conversations we have because I don’t feel like she’s hearing or understanding what I’m saying.. yes I’m still hurt she cheated on me and was lying to me I was trying to work things out with her and still am.. sorry I just have a lot on my mind and I am an over thinker if anyone has any advice please share with me just don’t judge