What is a marriage based on, if not on God? If you don’t have God in your life, if you don’t know Jesus personally, then what keeps your marriage going?
I guess it could be intense love for another. And as great as that is, very very few people have it. Otherwise, what’s to stop you from saying to your spouse: “Eh, I don’t feel like being with you anymore.”??? It’s nothing but a legal formality in most states to just get a divorce.
When a christian has God, then God is the King of all of us, and we should all follow Him, in our marriages, and in everything else. And He says “I hate divorce!” (Malachi 2:16).
So we have that encouragement to stay together: a God who doesn’t want divorce, and promises us the strength to do His will in every situation (not that we always do, but the power to follow Him is promised).
Also, we have the Love that He gives us, to give to our spouses. If you don’t have His love to give, what kind of love do you have?