Ann is right. You need to get your hands on a copy of The Divorce Remedy (or it's predecessor Divorce Busting). Read it and get to know and understand it's principles. It might help you understand why this keeps happening in your marriage.
I also agree that you shouldn't be the one leaving the home. He's the one with the issues, so if you can take it, stick it out in the house.
Can you give us some more detail on your current situation? Do you have children? Are you still at home?
Peace, B
Me: 29 W: 28 T: 10 M: 7 No kids 2 Dogs and 1 Cat With Parents: 09/16/07 Apartment: 10/13/07 Back Home: ~2/16/2008