My boyfriend said exactly that to me last year before we went on a break. At first I thought there was someone else and actually there was but in the end they didn't get together, lol. Anyway, I think it was kind of just a phase because he's snapped out of it and now we're back together, better than ever. Don't worry yourself about it hun - leave him to it, maybe just stand by for a little while and see if he snaps out of it any time soon, but don't wait around forever.