Mostly, we don't learn about how to treat each other from a book. We learn by watching. So here's the clue about how to choose a mate: Watch how their parents treat each other. If the Mom treats the Dad like he's a moron...well... don't be surprised if when you're married you get the same treatment...after the honeymoon, of course. If your guy's Dad treats the wife with respect, grace and dignity, then you're probably getting a good guy.
Every fight, every conversation, every gift, every hug is a lesson in pre-marital counseling for those looking on. Even when the kids roll their eyes!
Now you may not have the same respect for your parents as we do. You may look at his parents and groan. That doesn't mean you have to be a statistic or another casualty. You can break the mold! We have many friends that are not repeating the cycles of their family. God's grace can break those destructive patterns.
But if you happen to be one of those who is considering marriage, it's a good idea to check out the parents. It may speed up your decision!