Misunderstanding relationships

My autistic son wants to be like everyone else and have a partner, home etc.  he encounters women at the gym and work and he goes headlong into building relationships with them but he is clumsy, direct and full on.  Unfortunately he comes across as inappropriate and a little odd.  How do we advise him to take a step back.  Whenever we approach the subject he just accuses us of interfering with his friends.  We are worried someone will not understand him.