You are totally over reacting that is the past. If you can't let the past go than you don't need to be with him.My ex fiance was a virgin when I met him and I had a few sexual encouters with men before him. He completly understood that it was part of my past and it never changed anything between us. I didn't cheat on him that's what mattered. As long as he didn't cheat on you with any of those girls than there is nothing wrong with what he did. He is a young guy and many young guys do that. They have many sexual partners. You are expecting too much from a man at that age to be a virgin. You really need to decide can you handle it or are you going to walk away.Its not fair to him that you are pissed about his past. The past is the past and you need to move on.