HELP! He's grinding away my sleepy time!

The Sean started grinding his teeth in his sleep! AAARGH! It wakes me up everytime! I think this is worse than him waking me up every 2hours to feed when he was an infant. *sad moment....i don't have a baby anymore :'( Anyways it hurts my teeth just thinking about it. I read that stress can cause it but I've tried my best to eliminate what could be causing him stress but it doesn't seem to help it. I don't know what to do. I don't want him to grind his little teefies away.....Poor guy....Poor me! lol