If all you are in a relationship for is the sex then it isn't a relationship, you are only using the other person and like an idiot they are allowing you to do so.
IF you loved him you wouldn't be so selfish, you would be proud that your boyfriend was doing something to protect the rights of your fellow citizens and you would be proud to wait for such a selfless man. Instead you are whining "how am I going to cope when he's away". It isn't about YOU...