I know that sounds awful, but I just can't think what else to do.
She's quite a close friend, they've been married nearly 20 years, and I know she will be devastated.
I found out a few months ago when another friend started working in the same place as her dh. It seems that it's been going on for several years, and is reasonably common knowledge around the workplace.
On the basis that it is such a long term thing, I really think my friend should know. I would be there for her as much or as little as she wants in order to get her through it.
BUT, I really really don't want to be the one to tell her. What if it ruins our friendship? What if she doesn't believe me? What if she wants to know why I didn't run round to tell her straight away? She's a lovely lovely friend, and as much as I think she should know this about her dh, I do not want to lose her friendship from my life 