You know, I get the tendency to analyze everything. I'm a world-class overthinker, too.
But there comes a time when analysis is paralysis and from an outsider perspective, you're past that point by a considerable distance.
I also wonder if his "addiction" to you isn't the tiniest bit gratifying to your ego? Especially since his history is being essentially unavailable...he's still married, right? Add in his history of cheating...
You're the only one who can decide when enough is enough.