I am normally quite sceptical of "Christian movies" because they are usually quite predictable and you sort of know the ending which is usually happy or as expected.
Fireproof is about two persons in a marriage. The marriage is on the rocks and they are about to get a divorce. The husband, Captain Caleb is a fire fighter and lives by the code that "never leave your partner behind." The wife is Catherine, a hospital administrator who is tempted to commit adultery. Caleb's father challenges his son to commit to a forty day test called "The Love Dare."
This movie is a good reminder that commitment to the Lord, who is the third person in a marriage is an effective way to "fireproof" a marriage.