How can i win my boyfriend back?

Me and my boyfriend have been going out for about 9 months. He just turned 19 and I am 21 lately HE has been talking a lot about marriage, before I met him mariage was not in the picture for me for a long time. But after I met him I realize that I could...

marry him and be happy. He even bought me a promise ring like 2 weeks ago. A few days after he bought me the ring he went to hang out with a friend thats a girl who he had not seen a long time. When I saw him again he told me that he still loved me but felt we were to serious now and needed to have more fun. Because he is only 19. So we decided to take a month long break and he has been dating different girls since then, as well as me. We are going on a trip to vegas to celebrate our anyversary since it has been planed in advance. But I dont know what to do to win him back. I have been telling him I've been going on dates but I havent gone on any I just dont feel right about it. The thing that bugs me the most is the fact that he doesnt seem affected to the fact that I am going on dates with guys. Me on the other hand it kills me to know and try not to talk about the dates he goes on. What can I do to get him back?

Nothing! he has made a choice to play you and keep you on the side and be with other girls and you are sitting there taking it! he is going to continue to be with other girls as long as your ok with it when your really not..you deserve someone who wants to be with only you and if this guy wants the best of both worlds and have you and other girls then you need to set him straight and tell him its either just me or nothing!