The Marriage Pact is a quasi sci-fi mystery by Michelle Richmond. It deals with a cult that ensures that marriages will last. Couples sign a lengthy contract with hundreds of rules they must abide by or they suffer extreme consequences. Maybe a great premise but so poorly executed that you never believe the story. There is some interest about what makes a marriage work. I guess the “mystery” is solved as the novel comes to a close but you won’t really care. Skip this book unless you can’t resist the premise.

https://en.wikipedia.org/wiki/Michelle_Richmond