I don't think it is tasteless to start this thread. If anyone thinks that, then the assumption is that this forum is simply for women whose partners have been unfaithful- and need support- and anyone who dares to talk about the other side is somehow out of order. Not so.
Interestingly, in the Sunday Times last week there was a feature (I didn't read it but someone has told me about it) which actually reinforces the gender stereotypes - through scientific research on brain waves- about women's and men's emotions and sex. The research based on MRI scans showed that women's emotions were much more engaged during sex than men's.
That aside, I think it is perfectly acceptable to broach this issue here.
Affairs happen for a reason. Yes, they do sometimes give women- or men- the final push to leave a relationship. It is generalising to say that anyone should regret an affair. Why should they? It may be that a woman or man has been in an abusive or emotionally dead marriage for years but lacked the courage to leave. No one is perfect- not everyone can leave before they begin something else.
I actually think it is better not to have regrets about anything, as regret is often a destructive. There are always consequences to any action ( for every action there is a reaction- basic physics)- but that is not the same as regret.
I also think that an affair is not necessarily the deal breaker or worst thing a human being can do to another. Think of violence, gambling, debt, alcohol abuse, drug abuse, emotional and sexual abuse within a marriage or perpetrated by a partner- surely these are worse than having sex with another person?
There are also women who have affairs because their man is useless at sex, or they have mis matched libidos, but who stay put for the sake of young children. If they are discreet, never found out and loyal in other ways- is that such a bad thing?