If I believe that my wife/girlfriend *has* to be hot or at least good looking for her age?

I mean, I have reasonable standards, and I know as people grow old, then the sands of time will cause unavoidable signs of age. However, I was just reading the last bit of the Mariah thread and there was a comment about "wait til your wife spits out a couple of puppies"

Well, that's why I wouldn't let my wife have kids. Unless they undertook to work like hell to slim down and get sexy after the kid. Which is never easy, I understand that. You can get depessed, and the baby creates workload and it's not easy to do the hard yards required.

But I think it's a love and respect that each person in the relationship will keep themselves looking sexy for the other. Like I would think my partner is being very selfish if she let herself get ugly.

Basically, what I want to know is this:
Am I unreasonable if I require that my partner remains good looking and slim/at least average weight for me to continue in a relationship with her? (exception if it's not her fault, like if she got cancer and lost her hair, etc.)