Helen Fisher is an author, human behavior researcher, and anthropologist. She describes human romantic relationships in three stages : Lust. This stage is dominated by the physical act of sex, sexual gratification, and casual sex. Your attention is directed toward your potential partner and spending time with that specific person begins to be your primary focus. You and your partner form bonds and commit to each other in a way that provides calm and comfort. Within these three stages, the brain starts releasing hormones to reward you as you move through each stage. The lust stage is marked by increased levels of testosterone and estrogen to drive sexual desire and sexual satisfaction. In this stage, sex is the goal, and testosterone and estrogen are the drivers in moving two people toward that goal.
The interesting thing to know about limerence is that for most people it lasts between six and 24 months — three years if you are lucky. Then bang! Those chemicals abandon the body and they don't appear back unless you get another aficionado. This is where I look by people's narratives about love and femininity.