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Anybody who doesn't come to a relationship with baggage obviously has never gone anywhere. It's what you do with that baggage that forms the partnership. I feel bad for LW, but it's obvious she's dealing with a guy who is either completely clueless about the etiquette of a good marriage, or else he's a very accomplished passive-aggressive manipulator.
My advice is put a quick stop to all this angst and flailing around. The two of them need to just sit down and talk about it. From what she's written, I wouldn't think there had been any kind of deal-breaker in what's happened, but like everybody else, I'm just speculating. They've both done things that are hard to justify within the typical social contract of marriage, but they need to discuss those things between themselves and work out how this relationship is going to go into the future.
This is not the end of anything but the beginning of a long evolution of a real relationship – one that is formed and tempered by both parties involved speaking to each other, instead of about each other.