Playas beware: scientists have now isolated the gene for commitment and monogamy. And worse: they can transmit the gene through genetic engineering (at least in voles). Your roamin' days are numbered:
Scientists studying voles (mouse-like rodents) discovered that transferring a single gene, the vasopressin receptor, from the monogamous prairie vole into the brain's reward centre of a promiscuous meadow vole, would cause that meadow vole become monogamous.
Meanwhile, Swedish scientists have studied more than 500 twins and their spouses/domestic partners and have come to find that the vasopressin gene seems to have a similar effect on humans. “The researchers found that men with a particular variant of the AVPR1A gene (that codes for vasopressin in humans) scored lower on the bonding questions and were less likely to be married compared to men who did not have the variant…Also, men with two copies of the gene variant were twice as likely to report having had a relationship crisis with their marital spouse or partner in the last 12 months as men without the variant.”
Link - Thanks Dawn Govender!