It's not so clear-cut when you are in the shoes of someone who is being constantly lied to. You forget what it felt like to trust somebody (assuming you ever did), so you don't have total clarity of perception that you don't trust your partner. For me (a person with more than your average allotment of integrity), I felt like I was in a strange land, adapting to strange rules. What should Alice have said to Tweedle-Dee and Tweedle-Dum? I don't relate to people who lie. They are inhabitants of a country with unfamiliar norms. They tell you this or that and maybe you know it ain't so, but what then? They appear so convinced of their own statements and they seem so needful for you to be equally convinced. It's their assurances vs. your suspicions. Either they are lying or you have "trust issues". How can you know whether you might be the problem? Can you call somebody a liar to her face without proof? If not, can you walk away without giving any explanation?
I can't do that. I had to be certain I was in the right before I dealt that kind of a blow to my fiance and I had to state the reason he was being ****canned in clear and unambiguous terms. Snooping was part of that picture but in the end he actually told me about one of his indiscretions. (Snooping wasn't enough - all I found was wistful yearning for some ex-girlfriend. It didn't help me trust him, but I said I would marry him so I intended to do it.)
I think I can see your point of view, Alceste, because I've known situations where confusion, etc, restrict our choices. But unless I was confused, I would divorce anyone I didn't trust. That's just me, though. Other people have other values.