Eeeeee! I must confess the ending didn't make much sense to me either. I fast forwarded a lot hence a lot of stuff I didn't pay attention to. I think he moved to Mongolia for career advancements. But same like winterspel, the thing that bugged me the most is the fact that there was no closure of relationship between the OTP. I think it was left the way it did 'cause (I think) the Japanese society still has a more reserved view on older woman-younger man relationships. Maybe :D