Well..

I was about to say that. I know a couple who are really close to my family. They‘ve been married for over 20 years and are still very happy.

Are you sure they're happy? I'm sure they are, but domestic violence and general drifting apart is usually kept very hidden even to the people living inside of the house. It's not fair to assess someone else's relationship.

You just said it's not fair to assess someone else's relationship but you're assuming they could be hiding something sinister just cause they don't tell people about their issues