I definitely agree with Thrive’s assessment that the WS more often than not struggles with some sort of self esteem, self hatred, feelings of inadequacy, etc... I’d take it a step further and touch on the fact that most APs are the same way, even though that’s not really being covered here.
My exWS pulled the “you’re only staying for the kids” bit quite often. It really gets under my skin when I hear it now, and think back to all the times he “accused” me of it. For him, it was a sympathy ploy, I’m not sure if you feel the same about your WS. It was a way for him to get me to lament about how much I loved him, and how much I wanted things to work. And when I didn’t give him that positive reinforcement, he’d inevitably find it somewhere else. But, I didn’t feel like expressing feelings that I didn’t actually feel, just to make him feel better was my responsibility.
I have experience being the OW, and I have had many married men use their lack of an “emotionally/sexually fulfilling relationship” as justification for trying to hit on me, both online and in person. The point is, the more women “want” them, the better it makes them feel about themselves. But it’s a temporary high, and doesn’t address the underlying issues, so the lows set in again, their confidence plummets, and off they are again to get positive attention from whoever will give it to them.