Feelings. Fucked around and caught feelings for a coworker who I've known for almost a year.

Background: I knew she was interested in me the first time we met, I liked her, I was going to ask her her but decided against it because I was new at the company and was advised it's the not best idea to get romantically involved with a coworker.

Then she gets a boyfriend. Then we have a couple sneaky make-out sessions, throughout the last couple months, then we take things a little bit further. We chat, she really likes me, I really like her. But now I'm stuck.

I know I'll probably get shit from some people for hooking up with a girl with a bf, but ultimately it's her choice, especially when shes comes onto me. And now I'm in a position where I really like this chick with a boyfriend, the feeling is mutual, but I don't even know if I would want to date her considering she's cheating on her current bf. I don't even know if this is the right place to ask for advice about this but I thought I could vent to you guys. What are your thoughts?

TL;DR Coworker and I have strong feelings, she has a bf, I'm torn.