“Face it, most women want marriage, and they want to have children,” says Susan Heitler, Ph.D., author of The Power of Two. “If you’re withholding either or both, you’re inviting the risk of her turning to someone else who can make that commitment and give her children.”

The plan: Make it clear that you’re thinking of living together as a starting point.
Talk about the future. Talk about her in your future.

She Thinks You’ve Cheated

Revenge affairs are common. Women have them in an attempt to restore self-esteem and feel desirable again.

“It comes down to human nature,” Heitler says. “She’ll want to get even.” She won’t necessarily go out looking to hook up, but when she’s tempted, the fact that you’ve done it may weaken her self-control.

The plan: If you are cheating or have cheated before, confess and apologize.
A survey conducted by Peggy Vaughan, author of The Monogamy Myth, showed that 86 percent of couples who discussed one partner’s affair were still married, compared with 59 percent of couples who barely talked about it.

If you’re not cheating, you have one paranoid woman on your hands. She probably has low self-confidence. Your job: Compliment her, sincerely, specifically, and often.

“You can make her feel better about herself so she won’t become vulnerable to these unfounded suspicions,” Fischoff says.

She’s Not Getting Enough

Oxytocin, a hormone that plays a central role in our urge to bond, spikes to levels three to five times higher than usual just before orgasm. The hormone is more intense in females than in males, so women develop a stronger sense of bonding through sex.

“If the two of you are not having as much sex as you used to, she might interpret this as a sign that you don’t find her attractive and that you don’t love her,” Fischoff says. “She may seek someone outside the relationship to validate that she’s still sexually attractive.”

A so-so sex life could also mean you have unresolved problems between you. Research conducted by Shirley Glass, Ph.D., author of Not Just Friends, found that 79 percent of cheating women cited dissatisfaction in the marriage as the cause.

The plan: Have more sex.
If she’s the one who doesn’t want sex, investigate why. Fix it. Get naked.

She’s Ready to Bolt

One more reason a woman might cheat: She wants to dump you. Infidelity can break up couples, so she might cheat on purpose as an easy out.

David Buss, a Ph.D., a professor of psychology at the University of Texas at Austin and the author of The Evolution of Desire, asked 100 men and women which tactic they would use to get out of a bad relationship. One of the most common answers: Start an affair.

The plan: She sucks—let her go.
You’re free!

(http://www.flyguychronicles.com/2009/08/6-signs-shes-thinking-of-cheating/)