<human>: Give me the gist of the text in a nutshell

Some people might call this "the friendzone" but whatever. We were best friends for years, we dated for four months, I still haven't gotten over it properly, she's actually now got a boyfriend and unlike our relationship, they've actually fucked. We're still best friends now.

I've had relationships since then, but even though I've even had sex with one of those girls, I just can't stop going back to her. She still wants to be best friends and to be honest, I do too. But now whenever I think about her and her new boyfriend I just get so pissed off and angry and sad and I even hit myself at times because I feel like such a total failure about it etc.
<bot>: how do I abandon feelings for someone after crushing on them for years? Going off to uni tomorrow and need to get it out of the way now.