I think all of her steps are adults, so there truly is NO need for constant communication, if any. My DH hasn't spoken to BM since my SD was 18.

I do see a few responses above. 

I think if it is the youngest child getting married then all are adults.. your DH needs to explain to his kids when THEY call and tell them. "remember.. your mom and I are divorced.. we don't need to communicate.. if there is something about the wedding you have a question on.. please let me know... but I am not interested in jointly discussing this with your mother".

Your DH is the problem here - not BM. He's allowing her to take over in this manner and he's not setting limits.

No coparenting is needed when their children are grown adults, they can communicate on their own with DH. Ultimately, this falls entirely on DH to set limits on BM and you will have to decide how long you can live this way, because it's apparent that DH does not care about your feelings. 

I'm so sorry you are going through this. It sounds like the only time he put you before her was by her choice, when she wouldn't speak to him. I saw that you are hoping a therapist will get through to him, but i don't think that's possible. Nobody can force him to care about your feeings and put you first. He either does or doesn't. This bull crap with the texts is hurting you, and he doesn't care. You deserve better. The vindictive part of me wants you to leave him, then tell BM's DH about it, and let your DH and BM deal with the ensuing drama. However, the best thing for you to do is put yourself first (since your pathetic DH won't) get out, and live for yourself. That will clear the way for you to find a guy who treats you the right way. Living well is the best revenge. 

Right. He's getting an emotional need met by this interaction with BM and he doesn't want to give it up. He'd rather play dumb with his wife and pretend he has no idea what she's upset about.

OP - he needs a wake-up call here, I think, personally.  You've done therapy, you are sleeping on the couch - what is your next step?

I agree. Just because it's his ex-wife doesn't make it okay for him to have such an emotionally intense relationship with another woman. 

My DH's best friend is a woman - they go out to eat, to movies, etc - I'm fine with it.  But if he was texting her all day like this? HELL no. 

She gave valid points that you are the only one who is hurting, caving, compromising etc. I want to put this in a nice way, because I understand how diffidicult it is and how much you want your marriage to work and I don't want to upset you, but this is also on you. I mean this with regard to your capitulating to DH's wants, regardless of how much you have told him you don't like it, or won't stand for it, you still let it happen without much consequence to your DH.

It reminds me of children and how they will whinge and whine to get what they want. If it gets to a point where it is too irritating to the parent that they give in, the child learns that to get what they want all they have to do is whinge and whine. Same as some people in relationships where one partner is behaving in a way the other is hurt by, but when they are confronted they threaten to leave, so the hurt partner withdraws their complaint out of fear of being left. The badly having partner learns if they threaten to leave it will stop any complaints by their partner, thus they can continue doing as they please.

In your posts I have noticed you have stated many times how you have told your DH that you are hurt by something, or are not comfortable, or won't be doing something (read: going to the wedding), or won't accept a certain behaviour in your marriage. Yet, when push comes to shove you back down on your stand and your DH gets his own way. Leaving him, skids and BM happy, but you miserable and your marriage in tatters.

We teach people how to treat us. This is achieved by providing consenquences for actions. If we state consequences for particular actions but never actually give them, it negates the concept of the consequences. Everyone has leverage in a relationship, as transactional and callous as it may sound. Usually the leverage is not required to to be threatened or utilised as both partners want to act in ways which make the other comfortable and choose to minimalise behaviours which do or have the potential to cause the other partner harm. Unfortunately, using leverage seems to be a required aspect of your current relationship.

You and your DH both have leverage, yet he is the only one utlising his, and yours is going unused. Your DH is leverging his desire to behave inapproapriately with his ex wife and skids against your desire to continue with your mariage abd be treated with respect. It sounds unkind, which I don't mean it to be, but your DH knows or is confident enough that you are scared/upset/against divorce or setting non-negotiable boundaries with him, so he uses this veiled threat as leverage to be able to do what he wants as he does not think you are strong/capable/courageous enough to put boundaries up and actually leave him if he stomps them.

Now I know many people have told you to leave him, and there also have been some posters who have said it appears your DH is having an affair with BM, rekindling his love for her, or wants his old family back. I tend to agree with them, but who knows for sure? The issue of this though, YOU need to know the truth in this matter. It is essential for your mental health, happiness and future planning.

It is clear you want your marriage to work - but how much are you willing to put up with in order to stay married to this man? If you are willing to continue be treated in the way you have been with the real likelihood of it progressively getting worse, just to keep the marriage "in tact", then you need to stop complaining about it and accept it.

If, on the other hand, you are not willing to be treated with contempt and will only settle for a real marriage where both spouses come first, before any adult skids, and the BM is just a distant (nasty) memory, then you need to make that happen youself. Your DH has shown you time and time again that he will not put you or your marriage at the forefront, in fact he will jeopardize it for the sake of an ex and his adult kids wants. You can't want for him to wake up and smell the coffee on this one, it is up to you to make it happen. It is unfair, absolutely. Your DH should do this of his own accord, but he clearly isn't and is ignoring your feelings and mental health.

I would do one of two things. Firstly, as Delilah put it above, give your DH EXACTLY the same treatment he is giving you. Ignore any of his requests, rescind anything you agreed, put his feelings and needs last, and act as inappropriately as him with regard to pretneding you are single and mingling with other men. OR, sit him down and tell him once and for all if he does not cease immediate the following behaviours (list them and provide valid reasons why they are unacceptable to you and your marriage) and if he should CHOOSE to disregard your wishes then you will file for divorce. No caving, no compromise, you have to actually mean it and action it should it be required.

At this point in time your DH knows you may whinge and whine, but will end up allowing him to get away with everything that is hurting you, and disrespecting your marriage. Why would he stop his behaviours (not withstanding no normal loving spouse would behave like he is in the first place) when he knows you will not ever go through with anything that really affects him negatively and he doesn't think you will ever leave? He thinks you will just cop it, because that is what you've taught him!

I recommend having some time to reflect within yourself why you are caving, compromising etc when your DH isn't. Is it out of fear? If so, what is more scary to you - having your DH continue to behave like this and get worse with the passage of time, or leaving the situation? If your refletion says you are more scared of divorce, then accept DH for what he is, and what he is doing. If not, then stand up for yourself, remember your self worth, and refuse to continue in this relationship.

I really wish you the best. You have been put in a very unfair and unacceptable situation, which should not be your problem to fix. I really hope it can be resolved to provide you the happiness and respect you deserve.