Does Love Exist? Science has the answer

Oxytocin -  Oxytocin is a hormone released during orgasm (and during childbirth and breast-feeding). This may be the reason why sex is thought to bring couples closer together and be the “glue” that binds the relationship.  There is a dark side to oxytocin as well. It seems to play a role in needy, clinging behaviors and jealousy. Vasopressin - Scientists learned about the role of vasopressin in attachment by studying the prairie vole, a small creature that forms monogamous bonds like humans do. When male prairie voles were given a drug that suppresses vasopressin, they began neglecting their partners and not fighting off other male voles who wanted to mate with her.