I am right now, and frankly I am happy the fact that he used to date (well, FWB) my former best friend did not stop me.
They were friends first...they met at a club in 2004 and started hanging out. She was a virgin at the time, or at least that is what she told him, although I as her bestie knew better. Eventually it came out because she couldn't keep it in her pants. He was shocked and asked her if she was sure she wanted to "lose it" to him, then she blurted out it was all a lie and she wasn't really a virgin and slept with him. They then became FWB and remained as such for a few months. She would always verbalize her regret for sleeping with him (she was trying to save herself for marriage) to him, then again to me the next day. (For the record, I never knew any of the intimate details, only that they were sleeping together.) However, she would continue calling him whenever she was in the mood. I didn't know what to make of that, but I told her it probably wasn't right to play mind games. He tried to pursue a relationship; she did not want one. Finally, she stopped answering his calls and texts, saying he was "toxic" for her or something of that nature.
She and I stayed close till I started college in 2005, then we pretty much lost contact. She would send me a FB message every 6 months or so, just saying hi. Since most of the things she said to me regarding him were conversational, I forgot about them as she and I grew apart.
I forget how he and I became facebook friends, but in May of this year he sent me a friendly (as in innocent enough) message. I forgot all about it till I was going through my inbox one day in June and saw it, and decided to reply just to be nice. From there, we struck up a conversation on FB chat, then BBM, then we talked to each other on the phone, then he invited me to come see him in NC. It was on the phone that I brought up the whole "I can't take this any further, you used to date my BFF" and he played like he didn't know. Figuring that 6 years was long enough for the girl code thing to expire, I rolled with it, especially since I didn't expect anything to develop. Well, here we are in September and we are living together. She actually got pretty pissed when she found out, although she is the one that "dumped" him. I don't even know what to think of that. Anyway, for a few weeks, she was posting all these subliminal messages on FB about leftovers, then she blocked me from seeing her wall. It got pretty weird, considering I haven't spoken to her since June 2009 and they haven't talked since sometime in 2008 when she called him to ask if he lives in NC, then made mention that she was coming down for a few days to visit her boyfriend. Just lots of weird, immature things on her end regarding their past involvement and our current relationship.