For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
The gospel of Jesus Christ is cut and dry. The doctrines of forgiveness, grace, faith, love, and redemption are one size fit all. The Church does a good job testifying to it.
Marriage is as hard to manage for a believer as it is for an unbeliever. The divorce rates prove what I'm saying to be true.
I don't know if the church has any answers that the world doesn't have when relationships are the issue. Some of the answers here prove what I'm saying. One size doesn't fit everybody.
"Religion" won't fix a bad marriage. Jacob finally got it together as a person by the time he got to be an old man, but we never read where he fell in love with Leah. He loved Rachel until the day she died giving birth to Benjamin. Some things are the way they are and they are not going to change.
"Who sinned that this man was born blind"? No one, it is for the glory of God.
God didn't get Daniel out of the lions' den, king Darius did. God protected him while he was there. Daniel 6
God didn't take Shadrach, Meshach, and Abed Nego out of the fiery furnace, Nebuchadnezzar did. God protected them from the power of the fire. Daniel 3
God doesn't always deliver the unloved from a difficult relationship. But He is always willing to protect the unloved from the effects of the situation.
The key is to do as the hebrews boys did: they continued to put God first when the trouble showed up. I don't mean to make it sound simple, as if I can do it with my eyes closed, standing on my head. I just know what I read and I believe it.