My mother tells me regularly, "Darling, you know that you'd be utterly screwed if he left you, right?" And you know what, she ain't wrong.
Life as a single adult for me would mean alimony (Mr. Marvie put his career on hold when we had kids, and on semi-permanent hold when we became expats. I'd owe it to him, and we both know it.), and either child support or the costs of a kick-ass housekeeper/nanny/manager to keep us all fed, out of complete squalor, and mind the small ones while I was at work.
So yeah, I run those numbers. And then I bend over backwards to do something amazing for my husband because he makes our lifestyle possible. (I also regularly run the numbers on what it would cost for him to go back and get re-credentialed to teach, move the kids to the US, buy a car, and take care of all of them until he is earning money. Then I compare it to the Social Security Survivor's Benefit, our savings and life insurance policies. The paranoia of a sole-income family -- I want to make sure that should I be hit by a falling toilet seat, they're safe and taken care of.) I just don't see a whole lot of point of running a what-if scenario for if I'd never married and my kids didn't exist. Perhaps that's because we married young, but I'd probably be in BigLaw in Chicago or something else totally crazy. I like my life way better than that. :)