Three comments-
I have been married for 25 years and maintained friendships with a few women well until we were married 11 years and moved out of state. I even visited the woman I was dating before I met my wife, at her home in the Rockies a few years ago, of course I had my 15 year old son with me for whatever its worth. And she knew about the stop we were going to be making,
The key here is that if my wife gets upset or uncomfortable with any friendship I have in or out of work, that friendship is over. Sexual jealousy is one of the strongest and least rational emotions that we are capable of.
And my marriage is not worth any friendship or relationship or even e-mail exchange, if she has a problem with it. I don’t tell her to wait it out, I don’t try to prove her wrong, the resentment that this could engender might go on for a long time, whether deserved or not, and it is just not worth it.
The other key point.—if the husband is spending too much time with the colleague, either accompany him the next time he is helping with her household projects or invite her to dinner with hubby and the kids. This will clarify for this woman exactly what she kind of territory she is entering and I don’t believe that anyone sets out to be a housebreaker.
Last point,—issuing the ultimatum is not always a good idea. If he of the type that doesn’t like to be told what to do, he gravitates to the new buddy. If he looks at the situation and stays with his wife, resentment of being forced into it may lead to (once again) resentment that will not dissipate.
Better to tell him what you are going to do, and he can act accordingly
SRM