I love my wife very much. I'm perfectly happy knowing that my love is the product of chemical processes in my brain. Also, the happiness that arises therefrom is the product of chemical processes. Also the works of the poets and musicians. Also philosophy. The fact that we can understand a little of the chemistry behind them doesn't make them any less enjoyable. It's like you're saying that if we understand the botany behind pine trees we can't enjoy the books printed on the paper made from them.

And if you think love is an "accidental" by-product of our evolutionary history, you're much mistaken.