Let’s face it: spending years, much less a lifetime, in a committed relationship with only one person is tough.

Temptation is a motivator for diving headlong into affairs and with so many people divorcing, fooling around, avoiding commitment, or just plain getting tired of their mates, one has to ask: Is monogamy natural behavior for human beings?

A 1999 Cornell University study reports that humans are capable of being in love for only 18-30 months, and the identification of a biological cocktail within humans, generated when “falling in love” (the meet, mate, produce phase) made up of dopamine, phenylethylamine and oxytocin.

“What it boils down to is that once a couple has produced a child, there is no evolutionary imperative for the passion associated with the first flush of love, and the chemical cocktail that produces it dissipates,” says Cornell professor Cindy Hazan.

“I don’t think that any particular behavior can be said to be natural or not,” says Sacramento State professor Joanne Marrow, who teaches human sexuality. “Most human behavior is learned and culturally defined. Some (people) embrace (monogamy), some love it, some want to steer clear of it, some have mixed feelings about it.”

Throughout the animal kingdom, the practice of monogamy is almost nonexistent. Without social boundaries or emotions getting in the way, the birds and the bees are free to answer nature’s call and indulge their sexual urges. Scientifically speaking, sexual fidelity is just plain weird.

Men of virtually every species are easily excited, preferring sexual adventure with numerous partners, free of inhibition. Evolution benefits the man who plants his seed in as many places as possible, which ensures survival of his genetic material.

“Sperm is cheap,” says professor Ronald Coleman, animal behavior specialist. “Males produce lots of it, and it’s relatively painless for them to do so.”

Males store large supplies of sperm for willing customers. Still, not all women are buying.

Biologically speaking, females of many species are picky when choosing mates. They have fewer eggs than men do sperm cells, so they have fewer chances to make quality offspring.

“A woman gets one chance per child,” adds Coleman. “And she’s got to make the most of it. (In nature), in many cases, it’s the females saying, ‘Here I am. I’ve got these eggs. What have you got?'”

Science explains much about sexual behavior, including when and how intercourse occurs.

“Physiology determines the timing of sexual intercourse, the frequency,” says professor William Lancaster, anatomy specialist. “But it comes into culture as well, and it’s evolved through human cultures for a long time. All sexual behavior is controlled by the brain.”

The brain indeed. In spite of what our bodies tell us, we make conscious choices to say “no” to temptation and “yes” to our partners – when we want to.

Joanne Marrow muses about a tale of long term commitment. “I read a very romantic story that was actually true about a couple in North Carolina who had been married something like 80 years. They got married when they were 15, and they died within one minute of each other in a nursing home. This is at least one example of people who’ve had a long life and had one partner.”

Scientific and evolutionary data reveal much about traditional human mating habits of the past, but today’s sexual climate is a tad different. We worry about STDs and birth control, and often have sex for pleasure instead of reproduction. There’s also homosexuality, far from a new lifestyle, which evolutionary science seems to be at a loss to explain.

“We’re meant to pair in pairs, whether they’re homosexual pairs or heterosexual pairs. I think that’s a very natural thing,” says psychologist Jennifer Ray. “The success of individual relationships depends on so many factors.”

“Homosexuality is an interesting issue in biology,” says Coleman. “Many people get caught up in the issue of, ‘is it genetic?’

Homosexuality, in the purest sense, means that (if) the male doesn’t have sex with the female, than there’s no genes going anywhere. The implication (is) that, ‘Oh, this person has a gene for homosexuality.’ It could be that everyone has a gene for homosexuality.”

Sexual orientation aside, men are still men, and women are still women, no matter who they decide to jump into bed with. Yet, people are more than the sum of their horny, physical parts. They have hearts and minds too. And let’s not forget egos and a little thing called jealousy. Given that large numbers of violent crimes are committed because of sexual jealousy, it may pay to keep a libido in check.

“It’s pretty hard for most people’s egos to handle sexual dalliances,” says Ray, a psychologist. “Some relationships can recover, but usually there’s a tremendous amount of trust that’s been violated and hurt. That, for most people, is very hard to grapple with.”

Marrow comments, “Human jealousy is not (universal). People can work through jealousy and see that it’s an immature emotion. You don’t have to feel jealousy if you have really high self-esteem and you understand each other.”

Some may deem jealousy immature, but it’s certainly not going anywhere. Few people accept being cheated on, but there are those who accept their partner’s need to fool around.

“People can have a successful marriage and not be monogamous. (With) open marriages, people, before they get married, decide that it’s going to be okay to have other sexual partners. They’d rather have that agreement and be honest with each other than be shocked and feel betrayed that someone has had an affair.”

For many, however, this is easier said than done.”If it’s part of the couple’s consensus, that they’re going to have outside relationships,” counters Ray. “There’s not that many people that can pull that off. I think it’s pretty tough to do that.”

“You’re in charge of your own good time,” explains Marrow. “Part of the problem is that people don’t discuss this before they get married. They’re making a lot of assumptions without spelling (things) out with one another, and then they find out they’ve got different assumptions. And then the result is feeling that they’re lied to, feeling that they’re betrayed in all kinds of ways. People find out that they have different values after they’re married when they should have figured these things out beforehand.”

For people who find that their relationships aren’t always perfect, they may find that the key to a romantic union, monogamous or not, is taking the bitter with the sweet.

Ray says, “A lot of (people) never got past the fairytale notion, that ‘You’re going to fall madly in love and live happily ever after,’ as though that’s an effortless equation. I think that’s a very unrealistic idea. If people have that idea, it’s inevitable that they’ll be disappointed.”

“Over the course of time that individuals commit to and stay in a relationship,” says Laurie Bissett Grady, director of Health Education, “many things may change. People may change, their wants, needs. People often want their ‘partner’ to change.”

In a world full of creatures with healthy, varied sex drives, many might deem monogamy unnatural. Still, that doesn’t mean it’s bad. After all, lots of natural things are bad, like colds, brain tumors, and violent impulses. Yet, sexual boredom exists, and sexual variety can definitely spices things up.”

A relationship is complicated and requires a lot from a person,” advises Marrow. “And that means (you) have to do some self-development and think before you start a union (with someone).”

Monogamy, like all behavioral practices, is a matter of choice. Straight, gay, or somewhere in between, it’s up to the individual to decide what to do with it and how to treat a relationship.

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