Some scientists suggest that monogamy is genetic. If so, the Mexican grey wolf and the North American beaver may have a more dominant version of that gene than your average human with Venus in Sagittarius. But don't be too quick to judge. It’s estimated that only about 3 to 5 percent of the mammalian animal species (to which humans belong, don't forget) are monogamous.
People of all signs cheat, or don't cheat. The tendency is probably far more complicated than a gene, a family history or an over-abundance of Fire-sign energy in one's natal chart. If a monogamous relationship is what you want, then the best you can do is choose a partner who wants the same thing, and resolve to keep the interest alive.
Here's some cosmic advice to ward off the cheating urge. What sign is your partner?
Aries, Leo and Sagittarius lead with their passion. Keeping the relationship hot with these signs requires an extra effort on your part. They like surprises -- even though they may claim not to. And they crave the chemical release of adrenaline. That's what makes "strange" love so appealing. They’re also fiercely competitive, which you can use to your advantage. One strategy is to make sure they always know that there are others in the world who are attracted to you. A little jealousy goes a long way to keeping a Fire sign excited about having you exclusively.
Taurus, Virgo and Capricorn prefer a sense of security and constancy in relationships. They want to know they’re on solid ground with a partner, and if you breech their trust they just might start a quid-pro-quo situation. Holding on to the heart of an Earth sign requires day-to-day maintenance. They need material and physical proof of your love, as well as constant reminders that you’re not taking them for granted.
Gemini, Libra an Aquarius can flirt and have many friendships for years at a time without falling in love. They tend not to take love seriously until it's apparent that they’re with a person who really rocks their world. Air signs are intellectual and when they do fall in love, it's usually with a person who makes them think and laugh. Stop making them think and laugh and they will find a substitute -- a good book, a new program on television, an affair with a sexy professor. Keep an Air sign's attention by staying involved in the world -- read, update your style and always be abreast of current events and pop culture.
Cancer, Scorpio and Pisces need to feel soulfully connected to a mate. They form emotional attachments quickly and decide who’s right for them intuitively. Sometimes they fall for a match that doesn't make logical sense, but it seems to fulfill a karmic bond. Or maybe the other person just smells right. For Water signs, love is something mystical and they consider it futile to think too much about it. Keeping the relationship monogamous has something to do with making it sacred. Special rituals the two of you share together, the language you use with one another, the foods you enjoy together, the promises you keep, and the soulful sex you share… it all fortifies the bond. For Water signs, "sacred" and "monogamous" are synonyms.