i really don't know what to do, how to get rid of trauma or the actions i do from it

I think i should just say everything here, i was in long distance relationship for 1.5 years its been a year since breakup, she used to talk about guys from her classes, all the attention she used to get, at one point in the end everything started to surface, all the likes she gave other guys on ***, everyone whom she followed on snap or talked, her self told that she have had talked and said "ilikeyou" to someone else while being in relationship may she later had felt guilt and shared it, but all these things were too much, she lied a lot even when i was overthinking, said that my overthinking was only that but all came out to be true, we broke up she tried many times to dm me back apologize but i didnt let her. After this it all went down the drain for me i started consuming porn, started to get into ***, nsfw roleplay, new fanatasies like femdom, then it got worse where i was getting aroused from this memory of her talking about other quys and it became a cuck fetish, and i masterbated to those thoughts and captions of this thing related with her. i want to get rid of this fetish or fantasy, i want to get rid of this memory, i did quit not masterbating to these cuck captions that i created myself but did it recently again after a week, im going insane now, i really want to quit i am struggling a lot, i dont know where to go, please help me here