BM over here wasn't in love with DH, she just wanted him back for a paycheck and a nanny. Then, when he wouldn't go back, she was pissed that she got told, "No."

That's always been the real issue; she didn't get her way. She thought she would always be able to pull his strings because she had his daughter. Nope.

DH did no joint anything with her. Not one thing. Ever. He doesn't want to be in the same area code as her.

Unfortunately for you, you don't get a magic wand to wave and 'poof' BM away. No matter that Bm dumped SD prior, she's back and she is and will always be the child's mother. A selfish annoying one perhaps, but still Mommy.

But that doesn't mean your DH has do things such as joint birthday parties. I don't recommend them to begin with because most heard about from others here don't turn out well. I know my DS and ex-DIL tried one for GS a number of years ago and SM did not handle it well (even though everything as done appropriately and SM totally a co-partner in the planning and implementing. It just bothered SM to be around BM. SM didn't realize until plans were underway that she would have issues about her feelings surrounding the event. Ok. Nobody wants to not be able to enjoy the event so at was the one and only joint party. Let BM do her own cake and ice cream and family/friend party if she want one and you and DH do what you two plan to do on your end with family/friends. That's totally acceptable.

The school thing? BM can and should set up with the school a tour and meeting/introduction with the teacher and office staff if she wants to be involved and know where daughter attends. She'll also want to be included in classroom notifications of activities , classroom performance of SD on behavior and grades ect. Perhaps there is a online parent/teacher portal. BM should be able to do all that and be a involved with her child's education. With that said, no, there is no reason for DH and BM to have to go and register together. DH has primary and daughter goes to school primarily on Dad's time. You don't mention if they both have joint legal custody. BM should be o the contact list for pick-ups and emergencies , but should not be called prior to Dad if she lives the majority of school time with him. If there are afterschool days where BM will be picking SD up, the school needs to have her on the allowed list, just as you may be on the list. What you and BM should not do though is get into a Bitch fight over which lady should pick SD up....the kid and the school do not want to be in the middle of feuding BM and SM. It is hard sometimes, but you always have to keep in mind no matter how lousy a BM you think BM is (are she actually very well may be), is that Dad has the custody, not the SM. You are his partner and assist him of course. But BM can get a modification in CO that gives her first rights of refusal if perchance Dad himself is not available.

So yeah, it's not really all about just still playing family, BM does have some rights and she can pursue more through CO if Dad gets too hard ball with her. No to joint party. No to jointly having to be involved together in registration. Better to inform her and let her know she can do the school involvement on her own though than to tell her to f-off. She does have a right to know about her child's schooling and education.

In DH's case, she didn't want him just his sense of responsibility and of course his money. BUT, he was supposed to remain at her beck & Call and do everything she told (not asked) him too. He was not supposed to date, let alone move on with his life. He had a "daughter to think of now" although it was fine that she moved on with one of the guys she was sleeping with when they were together. Then he took up with that "red headed hussy" aka me, who had the nerve to tell him his lawyer sucked & he needed a new one.

Your situation is eerily similar to mine. BM cheated on SO and left him to be with her other love interest. When that relationship ended she waged an all out campaign to get back together with SO and "get their family back together" all for the good of SD4. Luckily, SO and I managed to work through it and our relationship actually improved for the better after all of that drama. I have a great relationship with my SD and she's best buddies with my BD.

However, BM still insists that they are "a family" and wants to do things like birthday parties and dance recitals and other things like that, without my presence. She's finally dating someone new and has (for the time being) given up on trying to patch things up with SO, so I guess we'll see if her BF is going to be included in these events. SD's birthday is coming up, I'll be interested to see how the whole thing plays out!

These BM's don't let go until they MOVE ON. All you can do is be strong in your marriage, and hope that some new sucker comes along to fill BM's void. Haha!

In our case plan B hasn't failed yet but I don't think it brought her the happiness she was looking for so she takes it out on DH.

I think it is a control and pride thing. My XW was like this. We had no spawn but after she moved out of our marrital home to move in with her geriatric Fortune 500 executive sugar daddy she would call me regularly for lunch, offers for nooner hotel hookups, etc.... I never partook of her hookup offers and once our divorce was final I had as little as possible to do with her. Even then she would call me when she had some personal life crisis to work through. We still owned a home together so she had my number but once the house sold I never answered another of her calls or corresponence. Unfortunately the house did not sell until 3.5ish years after our divorce was final so I did have to suffer a number of her approaches before we were completely through. After I finally cut her off of all contact she did try an end run through some former mutual freinds wanting to know why I hated her so much that I would not speak with her. I did not honor that attempt with a response.

Interestingly I still get calls from friends who live in that same city as my XW with updates on her pathetic characterless life. Multiple out of wedlock spawn while cheating on her serial husbands. The last I heard she is on DH #3. I was #1. She and my ILs are also periodically in the local paper for their criminal activities. My XFIL is a former city councilman and my XMIL is a convicted federal felon. The whole family was sued by my XMIL's employer to recover $millions that were embezzled from his business during the time my XMIL was his business manager/book keeper. My XW was stuck with paying back a couple of $Mil. Fortunately that all went down ~19 years after we divorced so it had no impact on me.

My mom and dad ran into my XSIL at breakfast not too long ago. She commented that my XW periodically comments that her life was so much better with me. Ha! Yep. No doubt about that. Until she screwed it up.

Beyond a shared spawn, control, and pride I don't know what else could keep an X so enamored with a former spouse besides a mental disorder.