It is not extreme. Men who marry a young lady and build a life, family, children and career with her - and then leave her for a younger model once they are well established - is a common trope for a reason.
Obviously it is not all the time but it is common.
I’d say that’s fairly uncommon as you laid out. Now, cheats with another women and the wife leaves? That’s more common. But he wouldn’t be working past 62 on average anyway (avg retirement age in the US is 62), why would you expect him to continue to pay till you die at hopefully 85-95? Just unrealistic.