They are coming at this from the wrong angle. People are human and there is no way to ensure future fidelity in the getting to know you process for marriage. Also, people change. Despite that not all men stray. There are many faithful and committed ones who don't step out nor do they practice polygamy.
A lot of us, myself included think of many scenarios of what could go wrong. Attempting to hedge bets and predict future behaviour. People are challenging. God knows the uncertainty of others generates relationship anxiety.
I will agree with you on one thing. It is more about faith over fear. At the end of the day a deep love and appreciation for IIahi will get you through whatever life has in store.
They want to put the cause of their disloyalty on a woman’s shoulders. There are women out there who have given the world to their men and done everything he wants. he STILL cheats.
This is why you only do a reasonable amount for these ungrateful little shits. They’re gonna cheat if you’re a good wife, they’re gonna cheat if you’re a bad wife. Damned if you, damned if you don’t. 
A man Will only be loyal if HE wants to be loyal. He chooses out of his own accord and free will. There is nothing a woman can do to make him loyal, so stop trying to make it seem like his loyalty has something to do with @Baarisiyomoos’s mother 
Men will cheat if THEY WANT to, there is nothing one can do to stop it. It is solely their decision to make
