Crush/Infatuation on a co-worker. I am married. Please help me with your advice?

I am married, but I feel so strongly attracted to someone at work. This guy finds the way to go see me to my cubicle, constantly sends me emails. I am not sure he is infatuated about me, but I know that I am. Please help, I need your advice. Should I tell me to stop looking for me, and should I tell him why? If it is just my imagination and he is not attracted to me, I don't want make a big a deal of something small. But I also need to stop seeing him because I really want/need to deal with this super crush I have on him.