Why? You’re the one who chose him/her. God doesn’t micro-manage your life in this current dispensation. You have a free will which you exercise every single day of your life, you are free to make choices, free to make decisions.
Are you going to thank God when you divorce “the one He gave you”? What happens when you reject the “one given to you by God” – are you going to repent for rejecting your “soul mate”?
You create your own circumstances during this dispensation.
I saw a car the other day with the bumper sticker “driven by Jesus” – so if and when that car has an accident – will it be the devil’s fault, or the fault of someone who drove negligently?