Am I a horrible person for doing this?

Bout two years ago I set two of my friends up I was really close with both of them especially him as I was going through some dark patches and I didn't realise he had grown to like me like that, like we were so close but I respected his relationship with a friend of mine who I wasn't as close with but she was still in my circle of friends. Anyway their relationship had been on the rocks for the last 9 months they kept breaking up then getting back together to fuck then one night at a party he kissed me and that's when I realised I kind of love him idk but it opened my eyes like how amazing he is and he told me everything that he felt trapped in his relationship and he stayed with his gf because she threatened to kill her self which she does every week but yeah so I thought about it for a while but now he's my bf and things are really good but I feel like such an aweful person for "betraying her friendship" having said this he was on a break when we kissed she has fully blown cheated on him months before, their relationship was over and why not live life but yeah she's now ignoring me and be a bich calling me a slut behind my back and everything so yeah do i cut her out my life, try to make peace, forgive her or fight back