Can someone really love more than one person at a time?  My boyfriend says he wants to have another girl friend and I think it’s just going to be trouble.  Celia, 24

Celia, there are different phases (or stages) of romantic love that are recognized everywhere around the world.  Lust is something we can all feel for more than one person.  Fans may all lust after a star they consider hot without ever feeling jealous of each other.   

The attraction phase of romantic love is a very intense time.  This is where lovers can be very insecure--they’ve just connected with someone--they’re really into this new person and they need a lot of assurance that this person wants to be with them.  They can get anxious if calls, emails and text messages aren’t returned quickly.  And they’re highly prone to feeling jealous if they have any sense that their new love shows an interest in anyone else.   

The next stage, the attachment phase, is a much more settled down time.  The fiery flames of passion convert into trusting embers of commitment and enduring love.  During this phase it’s possible to incorporate other love interests without encountering the kinds of jealous rages that happen during the attraction phase.  

Amongst the cultures of the world about 85% recognize polygamy (having more than one spouse) as a fully acceptable marital option.  Most of these practice polygyny (one husband with multiple wives), while just .05% practice polyandry (one wife with multiple husbands). Considering all the people in the world as opposed to all the unique (and small) cultures in the world about a third of us live in societies that allow open polygamy.  Even then about 20% of the men in those societies can afford to maintain multiple wives (and all the children that might then be produced).  In the Western world we tend to deal with our natural attraction for multiple partners through having secret affairs or getting divorced and remarried a lot.  Some people attempt to do this openly and ethically through the practice of polyamory.

My girlfriend and I have been living together for 6 months and I’m starting to feel a little itchy.  I do NOT want to end things with her--I’m just missing the intrigue of getting to know new women. She is afraid that if we open up the relationship, I will meet someone “better” and that she will become history.  What should I do?  Ted, 56

Ted, you are begging me to endorse the practice of polyamory for you and your sweetie.  I can’t honestly do that because the decision to open up a relationship vis-a-viz polyamory is by design mutual.  Both of you would need to see value in having a consensual agreement to share intimacy with others.  Why then do people do this and how do they make it work?

People who embrace polyamory seek to live in integrity with the fact that humans are by nature a non-monogamous species.  Certainly this can readily be supported by our sexual dimorphism (where males are on average larger than females) and the relatively large male testes (which can produce sufficient sperm to engage in inter-uterine sperm competition).  Nonetheless, polyamory isn’t right for everyone.  It seems to work best for people who are beyond the attraction phase of romantic love and who either have a very strong foundation OR are not fearful of losing each other.  For some couples polyamory is serial monogamy in slow motion.

By allowing each other to become romantically involved with others they endorse the possibility that one or both of them might eventually find someone who pleases them more.  

Polyamorous couples with a strong foundation embrace compersion, (opposite of jealousy) wherein they find joy and pleasure in their partners enjoying intimacy with others.  Ultimately these couples  benefit from simultaneously participating in two worlds--one the stable home-life and the other, the adventure of kindling eros wherever and however it occurs.

How can you tell (by symbols and behavior) if your partner has multiple partners? Ken, 21

Ken, embedded in your question there appears to be anxiety about the thought of your partner having other partners.  If the truth be known humans are not wired for sexual fidelity.  Males are wired to spread their seed however they might--either investing fully into one partner and the children they create together, engaging every attractive woman they meet just in case she might respond or living polygynously and investing fully in more than one sweetie.  As for women, economics can play a big part in how faithful a woman is.  Women who are financially independent (or capable of being so), tend to be less faithful.  They are not trading sexual access for resources, but rather are choosing to have sex on their own terms.  Meanwhile women with no partner in particular may find it most beneficial to give all the males they engage, the impression that each of them could be the only one.  That way whatever each male would feel motivated to provision her fully.

Certainly there are the proverbial signs of infidelity--unexplained absences, changes in sexual appetites and preferences and new-found passions and interests.  For people who embrace polyamory, these changes would be regarded positively.  The primary couple might come to regard connections forged with others as adding to the vitality of their own relationship.  Upon returning from a visit with a lover, their good spirits and elevated sexual energy might enhance the love and regard the home partners have for each other.

In Western society we relish the sensation of being “the one.”  Anything that compromises that sensation feels dangerous.  The inherent problem here is that “attraction” phase romantic love sensations eventually fade, creating an uncomfortable physical and emotional vacancy.  Finding a new lover is often the surest way to satisfy that emptiness.

I recently slept with a friend of mine who is in a monogamous relationship with his live-in girlfriend. I'm single. I feel like I've hurt her as a women, that we should have some form of solidarity. I'm stuck with guilt and shame. Is this normal? -- Rosey, 36

Rosey, generally I wouldn't advise sleeping with people who report that they are in monogamous relationships. It invites a level of drama that typically has just about nothing to do with you...and much to do with their need to feel free(er).

Rather you might have encouraged your male friend to take the conversation back to his girlfriend rather than act out his feelings of confinement with you.   I imagine he told you that he loves you as a way to justify sleeping with you.  It’s probably best to not sleep with him again...and instead encourage him to bring the conversation back home.   As long as this never happens again, your girlfriends’ relationship will likely feel more secure if this single dalliance is not dangled in her face.  

Considering  that monogamy itself is a cultural construction (e.g. a human invention) that flies in the face of our genetic wiring, anyone who seeks to be monogamous is guided by cultural conventions, religion dictates and social reputation.    Generally the brain chemistry (high dopamine, high norepenephrine and low serotonin) last between two and four years.  Without the triangulation of children and shared projects, couples in their prime reproductive years are frequent candidates for clandestine encounters.