A young actor arrived home, excited, and told his flat mate he had a part in a movie. He was playing the husband of a feminist. "What a shame," said his friend. "I hoped you'd get a speaking part."
I think a relationship between two people who were both bent on saving the world would be a bit short of humour, especially if they held opposing views. Can you imagine the dinnertime conversation if HE had been campaigning for Romney and SHE had been campaigning for Obama.
Or, was your question rhetorical? I can't imagine a relationship without humour It would be so dull. I know a few people like this and I do NOT envy their lifestyle.