Well, you're young, want new experiences, but got into a long-distance relationship where you can only see each other a couple times a year. That is difficult, though not impossible, to make it work. However, maybe it just doesn't satisfy you anymore. There is nothing wrong with a relationship coming to an end if it has run its course. No relationship is guaranteed to last forever, and some aren't meant to - even if they are very good and bring us lots of fulfillment. It makes sense that you would prefer to be with the person who is in your life in the here and now rather than very far away. And maybe at your age, you're really not ready for such a big commitment like marrying your long-distance bf. Live a little before you do that. Don't beat yourself up or feel guilty. If you really and truly want to make the effort to keep up the LDR, then you will. If you find yourself not investing in it as much anymore, that could be telling you something - such as, it might be time to move on.
The world opens up... when you do.
"Oh, oh, can't you see? Love is the drug for me." ~Bryan Ferry
"Love and the self are one . . ." ~Leo Buscaglia "