This dude is one "but he gave me butterflies" situation away from being cucked. Even a random upper-tier normie could easily end up cucking him.
I bet it will happen eventually, especially since according to the guy, she's good looking. So it's just a matter of time.
Imagine you could easily fuck 10/10 females whenever you want. Would you be content with fucking only your unattractive GF just because well, you've got attached to her despite her looks, she cooks well, is funny or stuff like that ?
Of course not. The desire to know what it's like to have sex with someone you're actually sexually attracted to would be too strong. You would eventually cheat on her.
That's probably how things are for most women. They marry men they are not physically attracted to for plenty of reasons (he makes good money, he's kind, funny and so on), but eventually they meet Chad and they can't resist.
You know about that statistics about how genetics studies have shown that in prehistorical times about only one out of seventeen men had offspring or something ? I bet that doesn't mean they had no wives, it just means they were usually not the genitor of their kids. All it would take for their lineage to vanish with time would be for cucks to successfully impregnate their wives less often than Chad, since if I'm not mistaken, a sustained paternity fraud above 50% along numerous enough generations would ensure the disappearance of the cucks' male lineage.