Tell your wife the next time she brings it up, that being an atheist is only a stance on gods. If you're happy before, becoming one doesn't change it. What you do with your life, how elevated your feelings are and what you get out of existance has nothing to do with atheism.
When I was young, there was a god with infinite power protecting me. Is there anyone else who felt that way? And was sure about it? but the first time I fell in love, I was thrown down - or maybe I broke free - and I bade farewell to God and became human. Now I don't have God's protection, and I walk on the ground without wings, but I don't regret this hardship. I want to live as a person. -Arina Tanemura