Free The Brain in Love: 12 Lessons to Enhance Your Love Life by Daniel G. Amen Page B

PEA is known as the “love molecule” because it is what initiates the flood of chemicals into the brain along with norepinephrine and dopamine to create the feelings of euphoria and infatuation when we are highly attracted to someone.
    Commitment Chemicals—“I Love You”
(Oxytocin and Vasopressin)          
    For those of us who have had the wonderful experience of falling in love and being infatuated with someone, we also know that this amazing high and trancelike bliss does not last forever. We either progress into deeper love and commitment or make the decision to break apart and detach. Neuroscientists have determined that after a period of anywhere from six months to two years, the brain downshifts its response and the production of stimulating chemicals and levels of neurotransmitters like PEA start to drop off. It is the body’s innate wisdom to turn down the volume because it cannot maintain the lust-crazed state forever or people would eventually collapse with exhaustion. Several of my colleagues who do family and couples therapy note that a lot of unnecessary divorces and relationship breakups can occur during this timebecause people mistake the lack of intensity and euphoria as a sign that they have fallen out of love. Also because individuals may feel a withdrawal from the chemicals of infatuation, they may look for other sex partners, alcohol, or other substances to try to re-create the high. Understanding this phenomenon in advance can really help partners anticipate this phase and help them move into the next phase of trust and commitment where true love really begins. Once you find an attractive partner, how does your brain decide if you want to keep him or her? Commitment is usually harder for men than women. Even though our goals are the same (continuity of the species, pleasure, and connection), women are more oriented to raising children. There is not one human society where men are primary caretakers for kids. Men and women are wired differently. Women have a larger limbic or emotional brain. It doesn’t mean that men are not essential in childrearing or that they won’t help. They just have different roles. Unless women have experienced emotional trauma, they are usually more ready to settle down and start a family. Men are often frightened by the responsibilities involved in raising children and being faithful to one woman, which is easier for men who have lower testosterone levels. An American study of over four thousand men found that husbands with high testosterone levels were 43 percent more likely to get divorced and 38 percent more likely to have extramarital affairs than men with lower levels. They were also 50 percent less likely to get married at all. Men with the least amounts of testosterone were more likely to get married and to stay married, maybe because low testosterone levels make men calmer, less aggressive, less intense, and more cooperative. The desire to commit to someone is strongly linked to two other hormones of emotional bonding, oxytocin and vasopressin.
    Oxytocin
    Oxytocin is released by the pituitary gland and acts on the ovaries and testes to regulate reproduction. Researchers suspect that thishormone is important for forming close social bonds. The levels of this chemical rise when couples watch romantic movies, hug, or hold hands. Prairie voles, when injected with oxytocin, pair much faster than normally. Blocking oxytocin prevents them from bonding in a normal way. This is similar in humans, because couples bond to certain characteristics in each other. This is why you are attracted to the same type of man or woman repeatedly. In general, levels of oxytocin are lower in men, except after an orgasm, where they are raised more than 500 percent. This may explain why men feel very sleepy after an orgasm. This is the same hormone released in babies during breast-feeding, which makes them sleepy as well.
    Oxytocin is also related to the feelings of closeness