The ending seems abrupt and if you'd like to think of it deeply, it does make sense to have this kind of ending. I was actually expecting for him to commit suicide coz for me, that's the best end. But then again, disappearing like this is fine too. We do not know exactly what happened to him, if he's dead or alive but one thing is for sure, that he is finally at peace and in rest, away from the troubled past.
He's such a cutie but being his lover can be quite a pain because you really have to be patient all the time and you must feel deep love to him to begin with.