I like my best guy friend, and its complicated... ?

well...I'm 19, my name is nicole, I am in college. I came to college with a few close friends of mine, one of which I have a crush on, he is amazing. I went to high school with him, I've liked since freshman year...we weren't great friends then but I have worked my way up to being one of his best girl friends. The catch? Since the beginning of our senior year he had had a girlfriend up until recently, so that had ruled out the whole "him liking me" thing. He flirts with me a lot though, even when he was dating his girlfriend. He hugs a lot, always finds a way to touch me whether patting my arm or randomly running his hand in my hair, he compliments me a lot and says im cute and he says things that seem to cross the friendship line. For example since we have gotten to college he has been working out a lot and jokingly he flexed while our group of friends were all at a diner and he said "im trying to get buff for you, Nicole" and he smiled at me...that's not normal behavior is it? We hang out all the time, and I will start to get over him but all he has to do is say something cute or throw me a wink( which he does often) i fall back to square one....entirely smitten....My friends say that it seems like he likes me, but I always doubted that since he had a girlfriend, but as i said his relationship status has changed....i don't know what to do, i feel like if i tell him how i feel it would ruin our relationship, the one i worked so hard to gain, then again i want something more. My confidence sucks and im one of those shy girls, i think im stuck...any advice?