While it would be nice to have two parents who get along and live together harmoniously, one must accept the fact that they may need to live apart, or they may be happy with a disfunctional relationship. You shouldn't feel caught between them or feel like you will be the cause of conflict or separation. If you do feel that way, it is their fault for doing or saying things to make you feel like you are (or will be) somewhat to blame.

My parents are happy together (but aren't perfect, of course, like none of us are), so I probably can't totally identify. But good luck anyway, don't take it personally if they fall apart after you leave.