Boy Drama

Ok, here's the deal. During the beggining of the summer, my friends and I were just hanging in front of my house. We started playing with a handball and my insanely cute neighbor came outside andf started playing with us. We all started talking and we ALL liked him. He eventually asked on of my friends ourt and now they're boyfriend and girlfriend. The problem is, now he saying he likes me. He's insanely cute and he's super nice! He always suggests we not be alone together so nothing can happen, it's just that he's my best friend. Now, his girlfriend left for a week and we KISSED! We were both freaking out and now I can't see him until she gets back! Wich is nfair! He is my best friend! Now, I don't know what to so....any advice?