Otherwise you could end up with 5 divorces before you make a match.
This behavior is not at all unusual nor without reasonable expectation. Your typical Church of the Firstborn man or woman has an average of 5 spouses ~ check out Bill Clinton's mother and baby-daddy for an example!
Could you name specific cultures where that is true?
I trust you're not referring to your own behavior. Which is repugnant. The only "culture" which requires "proof of fertility" before marriage is an agar solution in a petri dish. Try selling your slop on a junior high school thread, Maypo brain. The adults are neither intrigued nor amused.
;^\