It appears I have no way of enforcing my boundary - which is that she does not communicate with the EAP while in the house, especially while I or the kids are there.
Remember, the purpose of your boundaries are to protect yourself emotionally/mentally/physically. For example, I am sure you feel terribly disrespected when your W contacts EAP, especially when you and the kids are home. You could say, "When you communicate with your EAP, it causes me to feel disrespected. I will not be disrespected in my own house". You might not want to limit it to just the house, and say, "I will not be disrespected". You have told her how it makes you feel. Your boundary is about not being disrespected. That should be the focus or point. Instead of shining the spotlight on her communicating with the OM, you are shining the light on disrespect. Then you declare that you will not be disrespected in your own home. You are not telling her what to do. Get it? She has a choice, and you are not telling her what to choose. You are simply stating that you won't tolerate disrespect. You are not threathening her, or giving an ultimatum. You have an obligation to yourself to protect that boundary. The next time you see her communicating with the OM, how can you protect your feelings of being disrespected?
Forget about what to do toher, for just a little while, okay? Yes, I stand by what I said about an effective boundary having stiff consequences if dishonored, but I think you are still being distracted by the consequences vs punishment. You are talking like you are defeated before even trying. So, for the time being, set aside what you could do to her. Just think about yourself. What could you do to defend yourself when experiencing disrespect? Have you ever had to stand up for yourself, face a bully, deal with disrespect in some other form from someone else? What did you do?
Considering your W's bold defiance and telling you she has no intentions of ending her contacts with the OM.......would I be wrong to think she has shown disrespect in other ways in the M? You may have thought it wasn't worth dealing with at that moment, or she'd accuse you of making too much out of it.....or you'd shrugg it off. You felt that keeping the peace was more important than having a fight about her tone of voice, eye rolling, heavy sighs, foot tapping, sarcasm, cursing, being rude in front of others, making you look like a dummy in front of your children.........the list is endless. It may have started out in a more less offensive behavior and over time it grew. Maybe it is so bad that her contemp shows in how she speaks to you, or the expression on her face, her body language, etc. Unfortunate, the nice guy H usually won't call out this type of bad behavior in his W, and her disrespect grows and she begins showing more and more rebellioun toward him and the MR.
Anyway, try to think about your feelings and how you can protect them. Don't give up and don't think of yourself as a victim. You have been wrongly treated, but you don't have to act like a helpless victim. You have choices, and you need to decide what is more important to you. And, you need to respect yourself.
Btw, don't offer to tell your WW other ways she can contact OM! Don't make deals about her continuing an EA. Don't accept the responsibility for her EA.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!