Guys are hard to argue with because we play by a different set of rules. But we defend ourselves to our last dying breath even when we KNOW we're wrong, because we hate admitting we messed up. Yes, we're trying to save face, but we're also trying to please the girl. If we admit we're wrong, we admit we didn't please her.

So when you do argue, don't rail on him for making bad choices (most of the time, he knows he did) And while its important to choose your battles, and let petty things slide, don't submit or let him win every time.

If you need to confront him about something, choose a calm moment. It's more likely than not he'll clamp up about the subject, but to get it out of him you have to lay yourself out first. And most importantly, stay calm. Any sign of stress from you, he's going to show it twice as much.