Search Results: how to get a boyfriend back

My best friend (WHO HAS A BOYFRIEND) of 6-7 years kissed a guy i used to hook up with.
Background
The guy and I had a horrible falling out, he said awful things and never apologized for them. My best friend has seen me cry over this guy. A year later he comes back to hanging around the friend group. I have a boyfriend now and i love him so much. The guy came up to me and said “we are cool” even though he never apologized so of course I hate him. He also tries so hard to become friends with my boyfriend, but of course he isn’t having it.
I just recently threw a party for my boyfriends birthday. The guy ended up showing up because of the mutual friends we have. Of course my boyfriend and I did everything in our power to avoid him all night, and he would still try and talk to me.
When I was dealing with a drunk person during the party my friend and the guy went to go get food. She got in his car!!! Of course it's the one time I wasn't in the room. Like an hour later they come back into the party with food, then my friend comes and stands next to me and doesn't say anything. There's also a chance they went to the bathroom together. The next day I ask her what happened and she admits that they kissed. She claimed she shut him down but then immediately contradicts herself with her next text. This is not the first time she has displayed “pick me” behavior
I guess it's just never been this bad. Her boyfriend emotionally cheated on her a month or 2 ago and ever since then she has been manipulating him. I also maybe feel sometimes she might be jealous of me, not on no cocky stuff.

The cheating aspect aside, do we think I should or. Ever can forgive her. Should jus let that bridge burn no matter how long we have been friends?