I'd say the main reason has little to do with personal dynamics and more to do with cultural/legal/religious differences. The advice you read on HS and HB is based on an American Protestant background/moral view subject to the sorts of civil marriage/divorce laws you find in US states. I'm from the US but I don't live in the US now so I know the difference. I believe MLC is not tied to culture. It's an illness with physical causes, but all illnesses are experienced and expressed in different ways in different cultures. And so the way it played out and is playing out for us isn't the same.
Maybe it bothers you but for me until now I see no reason to believe that my husband will wake up one day and decide to divorce me. I can't lie. He could, yes, in theory, but there's nothing now that points in that direction for me. I respect my husband and he asked for my patience from the outset, has been completely up front and transparent about what he is doing and why, told me what is going on now that I find hard to accept is temporary, and he has said he will stay with me forever and take care of me as long as that is what I want. Not because I asked that from him, but because that is what he feels inside him. His current behavior is totally MLC, which is why I am here, but I know his motivations and intentions too. In fact, you will find it hard to believe but he considers what he is doing for OUR mutual benefit, not just him. His BD with me was basically, "We've got this problem we are both facing. Here's how I want to solve it. Are you willing to stay with me or not while I do this?" That's the cultural difference of his MLC. He's taking on suffering for us. It would have been so much easier for him to dump me from the outset, and only think of himself, but he doesn't want to do that. So what am I supposed to do? Accuse him of lying?
Don't think I have it easier than you, in fact, what I am going through at the moment probably would be unbearable for most of you and you would have kicked your husband to the curb in a similar situation, but I believe the outcome in the end will be positive so I am willing to put up with suffering like this to get there. We promised eachother when we married that we would not abandon one another in hard times. He's not a great husband right now, but he is committed and respecting those vows to the best of his current ability. And I am trying to do the same. I don't have to apologize to anyone for that.