You made me wonder.

First result I got is this:

The phrase “happy wife, happy life” is believed to appear in 1903 in the final verse of choice bit of doggerel called “The Work and Wages Party” where the words have been not more than a congeries but used in expressing causality, it reads: “I’m a work and wages party man, I say that’s what I am.

But I also heard that archeologists found the saying on Egyptian tablets with hieroglyphics! :D