Yeah, avoiding answering and shifting the blame are two common strategies. In my experience, men can be real cowards, use the former, then when they're found out they use the latter to pretend they're the victime.
Not saying women don't do it, but as I've never dated one, I wouldn't really know.

You know you're in a healthy relationship when you don't see arguments as "who's going to win?" or "who's going to be right?" but as "as can we solve our problem together?". In the end, the winner is the relationship.

When you DID do something wrong, however, you should admit it. I do think I know more men than women who pretend they were right even after it's been proven they're not (although I know of women who do it too). I'm not sure if you're trying to be manly or what, but that's the attitude of a jerk. Owning up to one's mistakes take more guts than saying you didn't do it/ didn't do it on purpose/ didn't mean to do it or whatever.

Also, if you cheat on someone, don't go blaming them for it. That's just common sense. The relationship might have gone wrong, because of both of you, but the cheating is your fault. You should have discussed it before it came down to it, or you should own up now and admit you've messed up. Then, and only then, you'll be able to start talking about how it came down to it.

Also, I like when my fiancé is right and I'm wrong. It makes me admire him more for being even more clever than I am :p