Loving is risky. Yet love gives life meaning and promises unique moments of pleasure. Biology protects us in our quest for love and sexual happiness from false ideas about our romantic lives. It reveals the naivety of traditional sexual morals as well as the life-hostile nature of currently popular socio-political concepts. The hidden nature of love explains why we have sex—much more frequently and playfully than is necessary for reproduction. It describes the diversity of relationship forms and provides guidelines for finding the right partner. The evolutionary experiences stored in our genes reveal which behaviors are promising and which are not, and why we feel the way we do. For example, why life in a couple is the way it is.