As the title says... 
Few months ago I reconnected with an old friend and we kind of got close again really fast.. Few weeks after hanging out, in the middle of her panic attack she confessed me her feelings for me, the moment she said it it's like I started feeling the same towards her. Maybe it's because I've always looked at her as just a friend. 

Anyway, she knows I'm in a relationship, and we tried not to get physical or sexual but it slipped a few times since I really like spending time with her because we understand eachother so much.

She also has BPD and maybe that's part of the problem too. I kind of lost attraction for my boyfriend but at the same time I like this thrill but the guilt is eating me up. He doesn't deserve this, and I cannot confess this to him because I can't lose him, he means so much to me but I just lost that "being in love feeling".

Idk if I even need advice, I just feel like shit towards both of them and I hate myself for doing this.