What is considered cheating????

I find myself very attractive to one of my coworkers, am not happily married, but I have been with my man for 5 years. Me and this coworker have been flirting for months now. But today at work we took it to other level, he pull me into one of our Vacant rooms, we started kissing, and the next thing I know he was devouring my love flower.....is that considered Cheating