Why won’t he date me? What is the problem

This guy and I have been VERY close friends for over a year now. We have a connection like no other and we can’t live without each others presence. We started having sex and i obviously caught feelings but he never wanted a serious relationship so i backed off. Then we continued being friends again and we’ve been going strong for a long time. He recently dated a girl for a very short time and broke up with her. Now we’re having sex again but he still wont date me. We know everything about each other and we’re very close so what could be the problem?