I am ashamed I haven’t brought this up before but was scared of doing it in the wrong way, I could really do with some advice on how to approach it.
Don't feel ashamed, b/c you thought you were doing the right thing. Sometimes, I wish I could go back and clarify some of the 37 rules, b/c over the years I have seen people going a bit extreme with some of the rules. It's simply b/c they were written more in bullet point style, without sufficient explanations. So anyway.......we all learn, eh? I think we can figure out what your next step should be, or how you may need to address the elephant in the room.
I will be scared but I know I will just have to do it scared.
Exactly! All I ask is if you will run things by the board before you jump into some major decision or have a serious talk. LBS's tend to make more mistakes when they feel a spurt of inspiration or desperation (whichever) and don't discuss it with the board, or give the board time to reply. I don't want anyone getting dependent on the board to make their decisions, but I hope you understand what I'm trying to say.
It’s quite an eye opener to see that our successful joint commitment to R will only lead to the long difficult work of piecing.
LOL........yes, I see what you mean. However, if it will help your feelings, I let you in on something I believe about the LBH and piecing. I am not suggesting anyone agrees with me, okay? (Please forgive for taking the long road around to explain something you might feel doesn't apply at the moment, but it's how I try to explain it overall.) IMHO, the H's who are on the board, getting all the available tools offered to him.....is so much better prepared for Piecing than the average guy. Many H's will do a lot of their personal growth, reinvention, 180's. etc.,
before the couple ever reaches reconciliation. What he may, or may not, realize is that the WW's work cannot begin until she ends her affair. Some people may not see it as "work", but one of the hardest things she'll do is to successfully end all contact with her AP......and go through the withdrawals of that addiction. She has to get that OM out of head and leave him out (no fantasizing about what could have been, etc.) Until she does that work, the MR is not going to be everything is could be, b/c she has another guy in her head! To be fair, if I even dare use that word toward a WW, depression will probably go hand in hand with the withdrawals and even last for a while. If I need to expound why, I am up for the task.
So, what if the WW ends her affair, but no verbal commitment or reconciliation is made? This is where I will quickly question her lack of remorse and motivation. You see, she can make choices to show politeness, friendliness, affection, and basically act as if nothing ever happened. She can improve her all around behavior without her feeling one degree of remorse for how she treated her H. She should not be under the assumption that ending her affair automatically reconciled the MR. B/c a woman is capable of ending her A; go through withdrawals; and still not feel remorse. She can hang on to old resentment, disrespect, and self justification for a long time. Those very issues will prevent her from experiencing true and complete remorse, IMHO. She may be able to work on self improvement to a point, but that junk she has buried in her heart has to be healed or she's not going to experience the in-love feelings she wants. It's a process for the WW. It doesn't happen all in flash. Once she lets go of all that resentment and forgives her H for everything he's ever done.......I think she'll experience remorse for her own actions. I'm not saying the H should ask her to forgive him for everything. Please don't go there in some attempt to help her feel remorse,. This is something she has to process herself, and IMHO, it's part of the painful work she has to do. She has to overcome her pride, in order to feel remorse. If the H goes to her seeking forgiveness of things he isn't even aware exist, he will automatically set her up to continue blaming him for their problems, and she won't likely experience much humility if he's the scapegoat.
Just like her H needed tools, she will need tools also. He needs to realize that they have been on separate journeys, and coming back to the same one is going to be challenging. He's done all this work in hopes of saving himself and his M. He is excited when they reconcile, but when they enter into Piecing, he doesn't understand why she isn't showing the same level of effort, energy, interest, affection, etc. She has to process a lot and it doesn't come overnight for most. It's like being pregnant and giving birth. If she thought it was tough being pregnant, she doesn't know anything yet. Just wait till labor hits! The H did his thing beforehand, so his part of his job during the pregnancy and labor pains is to give her emotional support.
I can’t define my MR as in piecing as we haven’t discussed R, I haven’t given her my stipulations and she hasn’t verbally gone back on any of the things she has said at BD and since. Although her actions and behaviour look like she wants to R and has changed her mind on these things she hasn’t actually told me anything.
I don't think you are in Piecing, either. You are limbo, b/c nothing was said or settled, that I can tell. Here's what I am wondering. When you went back to the MBR,was it the night you returned home? I can't remember. And, were you intimate the night you returned to the MBR? If so, then there's a chance she is letting that event signify a reconciliation. If I were in her shoes, being intimate with my H would mean reconciliation........but that doesn't mean I actually said it in words. If my H never said he required anything from me......then I would
assume we were reconciled, since we were sleeping in the same room, having sex and pretty much going about like an ordinary couple. But that's me. Your W may be different. From what I've read, most all WW's will not take it upon themselves to do or say everything the H wants/needs if he stays quite about it. What's that old saying about silence gives consent?
They married about 20 years ago. They had no children and the marriage only lasted a couple of years, due to him having multiple A’s treating her very badly including violence and in the end being admitted to a psyche unit for serious mental difficulties, I think schizophrenia. He then abandoned her and she filed for D on that basis. He went back to his country and still lives over 5,000 miles away from us.
Oh wow! So, the idea that she would entertain the thought of going back to him.......is disturbing, to say the least. As I said in the previous post, this is a fantasy she has. IDK if he has convinced her that he is well and yada, yada.......but for whatever reason, she has some type of attachment. Regardless, it is unhealthy that she would even consider it. If I were you, therapy would definitely be on top of the list of requirements in going forward.
I met her the week her D was finalised, and we have been together 17 years with 2 beautiful children. I believe from what I’ve read that her fantasy is now to reunite with him when the kids have left. She has been living this fantasy in her EA for the last 3 years with him and is now dealing with withdrawals due to her recent decision to temporary cut off contact.
Is she demonstrating any particular symptoms, or are you going by the fact she has gone NC? How long has it been since last contact?
She refused to talk to me about it and even said things like “I can talk to who I want”, “you can’t control me” etc. I felt my only options were to wait or file.
It's not about you trying to control her. It is about your personal boundaries. When she M you, she was to forsake all others, which means not to be sexual with anyone else. If you google it, you will find a lot of additional opinions about that vow, so I might as well add mine. It means that no other person takes priority over her relationship with her H. If her H does not feel comfortable with her talking to another man......then by her own wedding vows, she should honor his feelings. If he is unreasonable, then she should divorce him, but don't continue communicating with some guy when your H has a problem with it. I am so sick of women playing the "you are trying to control me" card. She is the one manipulating you by playing that card, and don't you forget it. Men's b@lls tend to freeze up when their W plays the control card. (Sorry.........got on a rampage.)
You need to be secure in what you will do if she chooses not to honor your feelings. That is basically the function of enforcing boundaries.
My recent discovery that the EA was happening for years before BD has helped me realise, I have been duped. Last time I brought it up she looked me in the eyes and denied it. I am sure she will do anything she can to avoid admitting this, by denying, deflecting, minimising etc.
For some men, it seems important to prove what he knows to be true. Shoving the evidence in her face doesn't always bring a confession......as crazy as it may sound. You can't fix crazy! I don't recommend you show your sources of intell to her, b/c should she agree to your terms of reconciliation....you want to keep very close tabs on her communication with OM. So, don't give your sources away, no matter how much you want to push it into her face. If she denies, simply tell her you both know she's lying, and proceed with your alternative plan.......which should be to physically separate/divorce. As long as you are going to live under false pretenses and not do anything about it.......she'll play dumb. That's what WW do best.........play dumb! And, they play their H's for a dummy. (Sorry) You are no dummy. You are a good man, and one who loves his family. She's the dummy, and it sounds as if she needs professional therapy considering her XH previous track record.
Oh, I written too much. So, we can continue once you reply.
We stress "no R talk" so much, I guess people think it is off the table even if they are trying to reconcile. However, I think your problem here is that you don't know where the MR stands. Like some other board members, you are stuck in limbo b/c you don't feel like it is really a reconciliation, but you are in the MBR and having sex.....and she's being nicer. 
Don't let her get the focus on her not being able to trust "you". She is the one who has had the secret EA. She is the one who violated trust in the MR. WW's are sly, so stay on your toes.