Loki
Ah. This I have more than my share of experience in.
So he wishes to use you for his own amusement. Which is fine, if you do not want to get attached. If you do or are attached then do not. There is nothing but drama and theatrics and anger in such a path and really it is only enjoyable for a cuckolded weekend. If you intend to have your heart involved it will do nothing but break it and you must face it knowing that there is no other possibility.