Since I am dealing with this now in my own marriage, I have to agree with what Angelbear said....I have even asked him does she think you'll stay with her after what you did here??  IMHO, I feel that if you're in a committed relationship you can have friendships ONLY with the other gender but when it comes to the other parts of your relationship that's between you and your partner.

Darc

While infedelity played a small part in the dimise of my marriage it wasn't the foremost reason.  However my ex started "messing" with his office asstant and almost 10 years later he is still "messing" with her.  They have never married, he has no intentions of getting married again, although she did want to get married and have a family he set her straight on that and she left for a time, went back to live with her parents in Texas.  I guess they had enough with her, she was nearing 40 and they didn't want her living with them.  So she packed up and went back with my ex.  Every now and then when reality rears it's ugly head in the middle of her "happy family" fantasy she goes back to Texas, why my ex keeps taking her back is anyone's guess maybe it's guilt?  Being friends with most of his family I often hear about how "lonely" he is, his family doesn't like his girlfriend, she is never invited to any family events.  So either he shows up to the family events without her or he doesn't go.  Being from a very close knit Italian family though I know this bothers him.  There wasn't a holiday, birthday Baptisim we didn't attend and I know he doesn't like being "out of the loop" 

I say dump the jerk.

Had an ex bf who tried that. He said he was drinking, it was the girl's fault. It was one more reason we broke up. It happened at my apt. so I saw it.

I wouldn't trust a man that does that.

I see it as a betrayal and have no patience for it. Bye Bye 2nd husband.

It soooo depends;  I could forgive a one night stand..  once.

 

I would not forgive a series of them or an affair.

 

I have a relative who has been having an affair for years. His wife knows about it and it has been the reason for a lot of arguments but she has never left. It seems they have a good relationship in many other areas, they do  love each other in their own way- and I guess the marriage works on a lot of other levels.

 

I'm certain I could not share my husbands love with another woman- and that's what this is.A strictly physical thing would be easier to deal with for me. Him loving someone else is another thing completely.

I've never been in that situation but reading what you wrote about her she is asking for a very unhappy life with that guy. Trust is primary and how could you have trust when he cheated even before marriage. The worst is yet to come for her.