In some ways, it would be better if I thought my H was an aberration - if I thought that it was just really bad luck that I ended up with someone who would do what he has done. Unfortunately, after coming to this site for nearly a year, I know too well that that is not the case - there are far too many others in the same boat.
Why would anyone have any confidence that relationships have much chance of being permanent, or that one's spouse is going to remain faithful? If my kids ever marry, how can I be happy for them, knowing too well that the probability of their spouse leaving them is so high? More importantly, how can they ever feel safe in a relationship, always waiting for the other shoe to drop?
I have learned that when one's spouse is irritable, it does mean they no longer love you. I have learned that you can't count on your spouse to tell the truth about what he is feeling, even when asked directly. I have learned that you can't count on your spouse giving you even the slightest hint if something you are doing or not doing bothers him. I have learned that it is essential to go along with whatever your spouse wants, and never expect him to consider what you want. I have learned that given the opportunity, most people will be unfaithful, and willingly give up their family and their values to pursue pleasure.
I have learned that people will blame their spouse for any problems in their lives. I have learned that they will have affairs, and then decide that they must have been unhappy in the marriage, or they wouldn't have had an affair. But yet the other spouse could not have known they were unhappy, could not have done anything about it, because the betrayer didn't know he was so unhappy, until, as I read somewhere, the OP told him so.