That's interesting. I've never really thought about these different interpretations. For me the phrase is more like you have suggested about joy and fulfillment for both. When my husband and I have disagreements, we sit down and talk about it until we find a path forward. We don't gloss over them, just so that on the surface I seem to be pleased. I'm not happy when he's unhappy and vice versa. So actually we should also use the phrase "Happy Husband, happy life", though that doesn't rhyme as beautifully. 😅