As I read the first post my mind immediately went to Nick and Nora. Funny, contentious but ultimately trusting of each other and have real chemistry. As a writer I'm a constant observer of people. There are very few couples like Nick and Nora Charles in the world...but the ones that do exist have incredibly happy and interesting relationships. They do not need drama or strife between them to be engaging to a reader/viewer. There is a similar dynamic in the fictional Charles' as there is to another couple I know so it is not purely fiction.
And this post made me remember a very popular TV show when I was growing up - Hart to Hart. It was about a ridiculously wealthy and loving couple who solved mysteries on the side. It lasted five seasons!
I would say no. If they are going though rough times I think that should be enough. However maybe you can add some outside force that threatens to separate them, and they hold on as hard as possible to what they have. Maybe something is risking them to be separated?
