Evio - I don't know if this helps, but it occurs to me that many cheaters, especially men, think of their cheating as their "private life". It's the compartmentalization that we often read about.....they have a family life with you and the kids, with certain roles, actions, activities, whatever.....and then they have what they regard as a "private life", which they often consider that they fund, and it's a type of recreation, or whatever that they think of as uniquely theirs....like a hobby, that they fund and that (to them) it has no effect on their other role of husband/father. As absurd as it sounds, I think many of them regard it like a golf hobby or hunting, etc. of course, they don't consider the impact mental, emotional, financial, and often physical (STDs) their "hobby" might have on their wife, or others. They don't think of the energy and time it might take away from the wife and family. They don't think about their vows. My father was a violent alcoholic - he didn't cheat as far as I know (I really don't think so) but the thought as long as he kept working and providing basic things like a home, food, etc, through his work, he was somehow entitled to this. It wasn't a "private" hobby in the sense that it happened in front of us and impacted us directly - it sure wasn't a secret - but many people think like this. I work and I'm entitled to a private life that I fund with MY income and it doesn't affect my home life because I still come home and spend family time, whatever. I think that's some of the psychology that goes into this. It's very limited, self serving thinking, but.....there it is. A lot of people, especially men, think like this, especially if they are not putting emotional investment into their APs, whatever type they are. Nor do I give any validity to this type of thinking, but I think even now, it's fairly common. It plays into the "what they don't know won't hurt them" mindset.
As for kids....I think many men are not as invested in their kids as mothers are, especially babies and small kids, and that may just be a biological thing. Women carry, nurse and take care of the little ones so they are inherently more bound to them than others who may care, but not as much. It's not as direct or personal. For many men, it might seem like more of an obligation than a joy. I do think biology dictates much in life, I know that's not a popular belief in society now, but I still think it's true. I think males in particular have to be trained by society to view the parental role as one involving deep commitment, modeling and attachment. Look how many men just skip out on their families entirely. I know some women do this, but it's a lot more men.
Just a few thoughts :)