I’m a homewrecker and I hate myself for it

Some background: I’m a student in college and had my first relationship for 9 months during the second half/ first quarter of my frosh and sophomore year. When I was in a relationship I was completely devoted to him and would never even consider cheating on him. So I don’t understand why some people can just make those decisions like being unfaithful to their SO.

Anyways, there was this guy I met at freshman orientation going into college and he was pretty cute (later found out he thought the same thing when we first met ) but I quickly found out he had a gf and they had been together for 2 ish years. Over time I never really thought about seeing him as anything more than a friend, even tho he was kinda cute and we were compatible. Fast forward to a couple weeks ago, I came over to his room and we randomly hooked up, completely sober. I told myself I wouldn’t do it again since I would hate to put myself in the SO’s shoes but I fucked up again. And again. And a lot more. Last night we spent the night and part of the day in bed together and he was wasted the night before, but told me he loved me. Which really fucked up my life because how could you say that to another girl if you’ve already promised to love your girlfriend? He apologized for what he said in the morning and I knew at that moment I needed to stop with the self-destructive behavior. Men truly aren’t shit but at the same time it takes two to tango. As much as I’d like to contact the gf and let her know that her bf is a POS, I can’t handle that type of responsibility, even tho if I were in her shoes I’d want to know. I feel awful for my actions but I’m getting help and know that I shouldn’t be anyone’s second option. It’s going to be hard to cut him off but I need to do it for my sanity and stop the destructive cycle. Sorry for the rant, I just needed to get this off my chest and please don’t comment anything super hurtful, I know what I did was messed up but I’m trying my best to fix what I can.