Back story:
My ex broke up with me 2 months ago. We have a 3 year old together. He told me he wasn't in love with me anymore and he started talking to another girl about a week after the break up. Not entirely sure if it was just friendly or not but it still hurt.
Anyway I was out for a friends birthday and her boyfriend is one of my ex's best friends, anyway we ended up going to a nightclub. My ex also had his work night out that night and he ended up in the same club. A part of me still loves him but I couldn't be bothered with any of the drama. Later on in the night some guy started dancing with me and I ended up kissing him. Not long after I turned around and he was talking to my friends boyfriend. I'm not sure as to whether he saw the kiss or not but i immediately felt guilty regardless of who broke up with who. At the end of the night me, my friend, her boyfriend and the guy I had kissed were outside waiting on taxis. My ex appeared and him and my friends boyfriend walked half way up the street having some form of chat then they came back and he said he was getting a taxi home and stormed off.
I don't know whether I should apologise in person when I next see him or what because I really would not want him to see that because I know I would of hated it if it was the other way about. But he might not even care anyway. I just don't want it to become more hostile because we have to communicate for our daughter. Help?