I had a surprisingly hard time thinking of any literary couple I particularly like. And then I remembered - Mike and Rebecca from the Monk Upstairs. She is busy busy busy; he was a monk for 20 years. There are elements of Mike and Rebecca both that remind me of me, and also elements of both that remind me of Brian, so they make a really interesting read. And I love the ways you see them compromise and stretch to support each other. I think they really do make each other better people.
Monk Upstairs is actually a sequel (to the Monk Downstairs) and I haven't read the first book yet - in which they become the couple. They were already well-established by the time I met them. I imagine it will be fun to see their history play out!