Cheater

An ex of mine and myself broke up in 2013. He was very attracted to me, loved everything about me. Anyways fast forward to 2014, I met his new gf. We have been friends on and off since 2014. We had a 3 sum that year as well. Now 2019, I am in the middle of a divorce and have been hanging out with them a lot sending naughty pictures to each other and what not. Well I went and hung out with my ex without her yesterday. Needless to say, he tried every way to get into my pants and almost ripped them! So I finally gave in. Just so you know he would leave me a lone. Well his fiance is my friend so I didn't want this going on and I told him he needed to tell her. He said no that's not a good idea. I told him I didn't want to live a lie. Well, since i wanted him to be honest with her, now she don't want nothing to do with me. He told me they are a couple who like to have fun with other women but apparently not 1 on 1 time. She confronted me thru text which is fine, I told her I'm sorry and I know what your all thinking too. I'm to blame bc I let him do it. I am to blame but it was not worth it at all! Now she doesn't want to be friends and told me she never wanted to fuck me. When I know that's not true. She did. I feel so damn bad, like it wasn't even worth it. I gave her my side of the story, which still wasn't helpful. I'm so disappointed in myself for not kicking him in the balls or doing something to help my situation. Theres absolutely nothing I can do to win her trust back and that sucks. I feel ashamed and ignorant. I know as I should feel that way.