It's always difficult to come to terms with this form of betrayal, particularly if there had been no warning signals. She could have been as jolly as Santa, calm and, seemingly, pleased with the way things were going between you two.
In contrast, the relationship could have been showing signs of deterioration for some time and although you both may have been unhappy for a while, it doesn't soften the blow or by no means excuse her disloyalty... unless you've cheated before (that, fellas, is called karma!).
There's a myriad of motives that could have prompted her to play away so read on as we reveal 10 reasons why women cheat.
"She might plunge into a 'revenge-fling' as payback if you've had an affair yourself or hurt her badly in some way," says relationship expert Dr Pam Spurr (www.drpam.co.uk). "Revenge-flings are almost always impulsive and she'll probably end up regretting it.
"It's the power of those painful feelings you've brought about in her, though, that get in the way of any rational thinking. I never recommend a revenge-fling as a way forward - two wrongs definitely don't make things right in a relationship that's been rocked by your previous affair or hurtful behaviour."
Unlike men, who are more likely to have an affair in order to fulfil their sexual needs, women take a more emotional approach by questioning their partner's low sex drive and often taking it personally, says Susan Quilliam, author of the book The New Joy Of Sex (published by Mitchell Beazley).
"Women put much more thought into emotional gratification," says Quilliam. "Whereas men are more likely to have an affair if they're sexually dissatisfied, women will question their partner's loyalty or assume that their man isn't in love with them anymore because they're no longer having sex." This could possibly lead to her seeking comfort in someone else's arms.
She feels neglected
"Don't underestimate how much feelings of neglect can drive a woman to make a bad choice and seek attention from another man," says Spurr. "Obviously it's always better for her to tell you clearly when she feels neglected but sometimes us women are guilty of believing that men are mind-readers.
If you're fortunate enough to be blessed with good genes and, as a result, receive a lot of attention from other women, it's possible that your partner may have an affair to make the point that you're not the only one who can turn heads.
"It isn't a matter of revenge, but rather her making the point that she is attractive too," says Susan. "She is making that point to herself as well as to you."
"For some women, as with some men, their ego needs constant stroking and boosting," says Spurr. "You can rarely give enough if a woman has such high maintenance needs. This is probably much more about her - and her emotional make-up - than you!
"She'll have an affair because she just loves the thrill of the passion and subterfuge. She relishes the way he makes her feel - and knowing she also has you to come home to. Until she sorts herself out, one man may rarely be enough."
She's bored of the relationship
Quilliam says that she receives a large number of letters from women who want to have an affair because their current relationship has gone sour. She says: "The relationship can be going on for years and, as time goes on, it starts to lose its spark.
"This is a very interesting one because not only can an affair end a relationship, but it can also be used as a transition into another," says Quilliam.
"She knows that if she has an affair with someone meaningless then you'll just walk away, leaving her single. But she might feel that she needs another relationship to go to before she splits up with you, so she might choose her next prey wisely before she goes in for the kill."
If she's disappointed in you
If your partner feels that you're constantly letting her down or that you're not the man she originally thought you were, she might find someone who she believes is more worthy of her attention, says Quilliam.
"She may have lost all respect for you - maybe because you're not good at your job or that you're a terrible father. If she's doing well and you're not, she won't see you as an equal. She might see you as someone she no longer admires or respects. It's tough, but it's one of the main reasons why women have affairs."
Quilliam says that some women are often driven into another man's arms without their partner doing anything wrong. It's simply a case of, "it's not you, it's me."
"If there has been a dramatic change in her life, she might have an affair," says Quilliam. "Maybe because she feels like her life has come to an end or that she has gone through a highly emotional experience. She might have an affair to compensate the shift in her life to make it mean more."
She wants to change you
It's no secret that some women often attempt to change their man and sometimes they have unusual ways of doing it. One method, says Quilliam, is to have an affair.
"She may feel that you don't take her seriously or that she cannot get through to you. This could possibly lead to her having an affair. She could use it as a way of communicating to you that you need to get your finger out and start doing what she wants."
Recommended books (downloadable pdfs):Tyler Durden - Responses To Leave Us Alone
Don Diebel - How To Talk To Single Women When On A Date
Labels: alpha male dating stupid pick up lines young online dating neil strauss and lisa women s body language g spot how to read human body language define body language neuro linguistic programming nlp training life coach effective verbal communication skills black alpha male