I wanted to jump in here because I see this come up a lot as a topic of confusion.
"Free will" is actually a Calvinist belief. Sure God lets us make decisions but God has many many persuasive ways to make sure that the decisions we make line up with His Will as He guides us back to Him.
God is soveriegn which mean NOTHING is impossible for him at all. That includes changing the path and heart of a man.
Many are the plans in a man's heart, but it is the LORD's purpose that prevails. Proverbs 19:21
The king's heart is in the hand of the LORD, as the rivers of water: he turneth it whithersoever he will. Proverbs 21:1
Another aspect of this is that when a husband and wife marry they form a covenant with God. Marriage is not between two, it is between three.
For the unbelieving husband is sanctified by the wife, and the unbelieving wife is sanctified by the husband, 1 Corinthians 7:14
It is IMPORTANT though that as we pray we are not praying to exert 'our' will upon our spouses and that we are praying from a pure heart and pure love. It is important that we focus our prayer on having God lead us and change us and for the salvation of our spouses to gain a relationship with God. We need to pray for God's Will to be done.
Often God speaks to people in a very profound way. Damascus road experiences happen all the time in people who have fallen away from God or maybe never even have known them.
(A Damascus road experience is when a person has an "awakening" and God speaks to them in a such a profound way that they immediately decide to make changes that line up with God's will for them. Saul's Damascus road ecperience is found in Acts 9.)
So naturally it comes back to our FAITH. Having a faith in God that all things are possible and having faith in God that His Will is the best choice for you and your family's life.
