Cut the chase,

I meet this girl which is in a relationship with her BF for two years or more but he is away (long distance). So one night it just happened between me and her HB8 and things started to be escalate from there. The problem is that I always have a crush on this girl of cause at the same time I do go out with different girls a well. We spent time together for 7months, and all those BF GF stuff people usually do not to mention I stop seeing other girls the whole duration when Im with her. Things got so serious and out of hand where we had sex as well ( she's a Virgin) *Bf din manage to have it for 2years. And right now the BF is back for for a coupe of months. And what bothers me a lot is that 2weeks ago we were on the same bed doing it and when he just got back for the first night they started to make out. So, the thing is at first I thought I just wanna have sex with this HB8 and close case you see. But I think it really starts to bother me a lot now as i cant stop thinking bout it. I suppose its a Oneitis. My first intention is of cause just to fool around and she has strong feelings for me as well. Going back to the BF she said would be more like oldtime sake or trying to work things out with him back (alot of problems in her relationship).
So the question is what do I do next? I really think Im in love with her and even if i get together with her I would be hard to find the trust. started wrongly at the first place.
Is she worth it? Help me out guys Thankss

From what I have heard, GFTOW.