I'm not so sure that most people seek love. I think most people seek approval. And we confuse that good feeling of being approved of as love. Hence, the 'honeymoon' stage. Who wouldn't feel good when someone is telling you that you are the greatest thing they've ever met?
THAT is what we miss when the honeymoon wanes. The constant positive feedback and approval. Since most people don't approve of themselves, first, when that goes away... you don't feel so good in the R anymore. Sound familiar to anyone?