Dr. Craig Keener says we should do everything possible to save the marriage, but ultimately we are not responsible for the actions of another person.
He explains, "If the marriage is taken away from you against your will, after you've done everything you can in love to preserve the marriage, God doesn't hold you accountable for that any more than He would hold a rape victim accountable for rape or a murder victim accountable for murder."
In Psalm 55 David cried out to God. He was in distress because a friend of his, someone he trusted and loved, had turned against him, becoming vicious and hateful. David's relationship with his friend had been severed because of the friend's sinful actions toward him. In response, David brought his anguish to God, giving God his burdens and trusting God to sustain him.
Perhaps some aspects of the relationship between David and his friend are similar to what you have faced with your former spouse.
David says, "If an enemy were insulting me, I could endure it; if a foe were raising himself against me, I could hide from him. But it is . . . my companion, my close friend, with whom I once enjoyed sweet fellowship. . . .
"War is in his heart; his words are more soothing than oil, yet they are drawn swords. Cast your cares on the LORD and he will sustain you; he will never let the righteous fall" (Psalm 55:12-14, 21-22).