I'm so glad you posted. Your thread got locked and I couldn't respond.
What I was going to write was that, as suggested by the famous Brandeis quote, "sunlight is the best disinfectant."
For so many years he has been able to walk among everyone in his life with his head held high as some kind of noble gentleman, who, while a good guy, just didn't want to be married anymore.
Instead, he is an adulterer of a woman who is a tyrant to those around her and uses her influence to have her way while her poor cuckolded husband dodders along looking the fool.
I was going to suggest that you tell him what you knew and that you go so far as to tell her husband. Aren't you after all irate that these people never told you.
I know there is a lot of to do over whether to reveal, but the circumstances here are different. I'm not saying you need to publicly shame him, but I'm so happy you told him.
If he and Bubbles carry on, then at least it is without the excitement, without the confidence that they are are so sly that no one has seen it. They do it with full knowledge that that their actions are seen and felt.
To that end, unless your daughters have asked you not to, I would also let him know that they know. Secrets in a family cause destruction. Pure and simple. Your daughters are adult. You did no wrong discussing this with them.
I don't know if it is the MLC or the narcissism, but mine continues to lie about everything. When I recently told him I knew he'd been messing with my passwords, he refused to have a discussion until I identified which I knew had been messed with. Even then he had excuses, no admissions, just more lies.
Your husband needs to man up. His office staff is fighting because he is a coward who won't lead. They don't create the pecking order. It is his office, he needs to do that. All they will do is peck each other's eyes out. He has created this mess and it is his to clean up.
In sum, good to you for telling. Now tell her husband and let him know his daughters know. Maybe it pushes them together, but at least it is more honest than what it is now. And, nothing destroys an affair faster than a little reality.