How can I approach this guy that I have been a total brat towards.?

I got out of a really hurtful and pointless relationship two months ago. My neighbor became friends with my roommates immediately (2 days) after my ex moved out. The last thing that I needed was this really attractive guy hanging out all the time while I was trying to heal.But he was there everyday and I refused to hide that I was hurt and angry. I can't justify being fake. My bitterness has since faded and I find myself becoming more attracted to him.I know that there were times I was harsh and sometimes he took it personally and went home, he always came back though. I have apologized to him, he does flirt with me, and I was just wondering what the best opener would be, since any ice that needs breaking was put there by me.