Concerning Christians and divorce, it appears Jesus gave only one reason for divorce, that is fornication. Paul on the other hand gave more of an Old Testament reasons for divorce. But, even he admits it's from him and not the LORD.
in 1 Corinthians, Paul transitions in verse 12 to say, “…I, not the Lord, say…” and then he addresses when an unbelieving spouse leaves the relationship. This does not question the inspiration of Scripture. Paul is just saying the Lord did not address abandonment. Jesus had not given any previous revelation on the subject. Paul says you don’t have to fight it if an unbeliever leaves a believer, and that remarriage is permissible for the offended spouse. Jesus said adultery is grounds for divorce. Paul gives us one other ground for divorce, abandonment. These are the only two.