How to make someone love you more?

I am gay. There is one person I met 9 months ago on Facebook. We started talking, and fell for each other pretty much, later we met, and got together few times and it was good. The only problem is that he lives in a different city than me, and we can't be together (in a relationship, or anything serious) but we managed to keep this going. I can sense that he kinda needs me for some reason, we've last for 9 months (?!) but there are moments when I'm not sure if he really loves me like I love him. I am aware that we are not together, that he has to have a life, sex, partners, and me too, till the moment we manage to be together, but he does sometimes some stuff and casually says some stuff which when I hear them, I become kinda jealous. How can I manage to make him want only me, like I want only him? How can I make him love only me, till the moment when we could be together? How to make him not wanting to meet another guys or girs, to make me the one for him? We have good relationship very casual and we keep it going, it's good, but not enough. I sense danger that I might lose him, that he can fall in love with someone else, I am far away, I am powerless. How to keep him? Please give me some advices, some tricks, something?