You must be in alot of heartache. I hope things will work out for you and your son eventually.
I dont't quite understand why he 'hit' you. Is it because you found out he is having a sexual relationship with his gf and you were against it?
Teenagers are very hormonal beings (if not more than same like pregnant women I dare say). I guess as parents, we must always practice patience with our children. Of course this is also easier said than done. One thing i know for sure, whenever something points to the direction of an argument, emotions should stay out. Again, easier said than done. But it does truly help if both parties are calm and not screaming at each other.