My coworker [30 M] tried to kiss Me [21 M] today at work.

After ignoring all forms of communication with my coworker for around a week (by the way, he isn't on the same department as me and doesn't sit anywhere close to me) he came over to say hi to me. This was around 5 today when almost everyone has left and no one was around us and we were hidden from anyone's view, but as I was standing up to get my coat cause I was cold ... he got really close to me and tried to kiss me. I leaned back, and quietly said "what are you doing" and he said "You know" quietly back. I looked at him and he looked at me for a couple of seconds. Then he just said "I'll see you around" and I said "okay"

I am just so confused. He is supposedly straight and married with two kids. I am bisexual, but have never thought about having any relationship with my coworkers. I know that I am starting to have feelings for him cause I missed talking to him for this week, but don't want to hurt his relationship and family. What should I do?

tl;dr: What should I do?