[openenglish]

I wouldn't leave... first try to reason with him, don't get angry, just sit down and talk and see if he understands you.

You could try to guilt him into listening to you by bringing up the huge favor that you did for him so he could stay in the country. Also bring up the fact that it is not fair that you should have to work more than everyone else, not just him.

If that doesn't work just try to ignore him and stop being his friend, maybe he'll stop being this way if he sees he can't walk all over you.

Also, is there someone else above him that you can talk to about it? It may be time to bring it to someone who is his boss.

Don't try to get revenge, it is most likely going to backfire. Just try to be reasonable and use your common sense.

Keep us updated, I hope it turns out OK.