Should I forget about him and just move on or keep trying to make it work?

This summer I was in Poland. And I had a whirl wind romance that I had not expected. At first I completely hated the guy, but then we became inseperable. He would say the sweetest things, talking about even marrige. He'd used to say I didn't want kids, when I came back to the states he'd tell me "We'll have as many kids as you'd like and I'll love them as much as I love you" He'd message me everyday and tell me how much he loved me and missed me. I honestly think we were completely in love. But after awhile, he stopped writing and we barely talk. He still tells me he loves me but I don't know. I'm going back next summer, but a years a long time. I can't stop thinking about him, everything in me wants to be with him forever. I always think about him and the love we shared this summer. I really love him, and I think he still loves me. But why won't he talk to me? And if I move on, can I forget this summer that changed my life and find someone new?