From what I have seen, unhappy marriages are very common in highly religious/conservative groups.

Most of these groups have stupid “No Sex before marriage” rules. So two horny young adults (teenagers in some cases) get married quickly. Pregnancy follows immediately and they start being parents before they are fully mature.

Fast forward 5-6 years later and they don’t even like each other anymore. The smart ones do the adult decision and divorce.

Way too many of them live misery constantly bickering while claiming to be “happily married” because “divorce is a sin”. They then spend most of their time complaining about their spouses. The kids of course have all sorts of baggage from growing up in the toxic environment.