I fail to see where I was "justifying" myself.

Infidelity happens a good deal more than the common man seems to believe it does, and that's a safe niche to occupy, but if you acknowledge that it happens as frequently is does, then you may want to consider the possibility that it isn't a manifestation of dysfunction so much as it is a default biological behavior. As I said, I think our societies' extreme attitude toward that behavior contributes to the problem.