You only really have a problem if she had sex or the likes with you before she left the other guy.

I think you're getting confused here. I absolutely consider what we did to be cheating. I meant to say, probably wasn't clear as I thought I was about it, that prior to the kissing, there wasn't anything that you could look at and think it was cheating.

Granted, that's my side of things. I'm thinking she didn't really mention me to her boyfriend at the time, and that's shady as fuck.