I don't know what to do HELP

I am in love with this guy I met in high schcool three years ago. We used to go out as friends and I started to really like him to the point were we started having really kinky chats. This all suddenly finished and I stopped seeing him when he went to college. Lately, so 2 years on I have been seeing him EVERYWHERE and its been really nice catching eachother. I went to a party with the guy I am supposedly dating the other day and boom in comes the boy I love, he pulls me over to one side and mentions about the chats we used to have jokingly and then asks if I have any feeling a still for him and then starts saying how he can't take his eyes off me. What do I do? I'm dating someone but I can't help but think of him! Am I in love?