It appears to me that if a person is struggling and unhappy in their marriage they have three primary choices.
A. They can continue to act and respond towards their partner as they have been doing and continue to be unhappy.
B. They can seek God for His wisdom, love and peace, regardless of what their partner does, and then with His help chose to act and react to their partner in ever more loving ways.
C. They can chose to make ungodly choices and suffer the misery that brings.
It really does come down to individual choice.