Why do people have different standards for different levels of attractive people?

I was initially dragged into a conversation.
People tend to keep different standards for different men.
I was shocked to know that the woman who was leading the conversation said something like" if he is my boyfriend I am willing to get married to him, have his kids and be a housewife I don't have issues.
Or else I am only going to stick to a short term relationship I don't want to sacrifice my career for someone like that"

Is it true for men as well?

In my mind the relationship thrives on the thing they do for each other without telling.
Efforts, support and understanding.
So from my perspective if I am in a relationship I will treat them as best as I can
Not less than others!
As far as my economic conditions and time I can spare with them.
Why do people have different standards for different levels of attractive people?
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