Curry: that is a really good question. There are several reasons: affairs are a maladjusted way of coping with problems (Subotnik) and as such are doomed to failure and more problems (every counsellor under the sun). The husband has poor coping skills and so to release his anxiety (healthy people do things like - open their mouths. Or write a letter. Or super healthy people phone Relate), he turns to a third party to lessen the intensity of the original bond. Affairs are a triangle (Cole) and are about the ego state of the INDIVIDUAL, not the wife or the marriage (Pittman). It is doubly unjust that she is blamed. But the OW is actually irrelevant. They are attracted to eachother, they act on that attraction, but they don't actually know eachother. They give eachother a lot of 'best behaviour' and admiration (which is false because they both know they are deceivers) - but they are strangers, projecting (Pittman). It is the 'forbidden' nature of affairs that give them their intensity. You will read on a lot of cheating threads 'we tried to stop it, but got back together'... this is used as proof of the luuuuuurve and 'this is bigger than both of us' - but the breakups are actually REQUIRED to keep the fantasy going and feed the addiction. If they spent to much time together, the gold plating starts rubbing off and the tarnish of two selfish immature people (the reality) dulls everything (Calder).
So this explains the other side of things: for a man looking to have his needs met, the OW meets some of those needs (intense admiration, ego boosting, excitement) and the wife meets the others (stability, family, homelife) (Harley). A man will ALWAYS want all his needs met, otherwise known as having his cake and eating it. Whilst the OW meets his most exciting needs, the wife actually meets MORE of his emotional needs. Therefore, the wife must separate immediately and withdraw all the meeting of those needs. He MUST lose his wife (Harley). You know, after you have f cked someone 100 different ways and said I love you 100 times in a week, what else is there? They start hearing 'Daddy' in their ear, wish to just come home to their own chair and their own cup of tea and their own quiet. And you don't know what you've lost till it's gone.
When men want to justify what they are doing (they can't possibly have anything wrong with them, so it must be the wife/marriage), they blame their spouse. She is a clingy nag. She doesn't keep the house clean (what I was told). She doesn't [fill in the blank]. All the time the wife clings weeps and begs, she is fulfilling his conviction that he is trapped, and causing him to cling to OW.
BUT: if she throws him out and starts living as though he never comes back, she is GIVING him the 'freedom' he so desperately says he wants, AND she is stating that she is worth more than this. He starts not liking the space he is in, OW starts to feel the clingy one, and he starts to respect the person he formerly despised. 'Gosh, I never thought she would react like this/I never knew she cared so much about me'.
~This is why us veterans advocate throwing him out. THROW him into OWs open, loving arms and open, loving legs, close the door and suddenly he isn't the one in control any more.
Sheesh. I know far too much about affairs.
'Affairs - the sacrifice of so much, for so little' - Frank Pittman