Is this common with pakistani women?

Yep.

It should go

Respect (at time of marriage) more than for any other woman out there (in his age range) → a lot more respect (after pregnancy)

instead of

little respect (at time of marriage) → ok now you have to get pregnant, otherwise, he’s going to go off and have affairs cuz he really doesn’t like you since you’re his momma’s choice and not his.