break up

Me and my boyfriend had been dating for a year and a half. I started noticing changes about a month ago just in his overall attitude and like initiative in the relationship. We love each other very much and have always said that we wouldn't leave each other. The day before Valentine's Day he was talking about seperating and I talked my side of the story which was just that we could work it out (he is moving in with his dad to another city about an hour away) (were 16) and he resolved it. Valentines it was fine and I gave him my present and da da da da da.Two days ago he was ignoring my texts and had a bland attitude and so he ended it. And I said I wanted him to be happy so I didn't fight as much for it. He says he's not happy with having a relationship now but I feel like we have always been happy. I don't understand the sudden mood change and he said he doesn't know if it will be temporary. Has anyone else experienced this? Thoughts?