Fallen for my “friends with benefits”

So I met this guy in early September, and we immediately hit it off. We started by hanging out twice a week (for the first two months) but now we see each other pretty much every day and talk everyday. He is the first person I’ve ever had a “relationship” with and we have gone from kissing to having sex a few times in one day (😛). I feel extremely comfortable with this guy and he is hands down one of my best friends. The problem is, that in the beginning, when we agreed to being FWB, he made it very clear that he doesnt want a relationship, but I’m positive that I’ve fallen in love with this kid. I’m going to be seeing him in a few days but I’m not sure if I want to tell him how I feel and risk ruining what we have, or just continue to have (great) sex and a wonderful friendship. Any advice??