Your son is a grown man - stay out of it unless he asks your advice. It's honestly none of your business how he co-parents with his ex-wife, or what happens in his relationship with his GF.

You really don't get to have a say if he's an adult. However, every family vibe is different. My dad will usually raise a question appoint something out, but then he backs off and doesn't try and advise my life. Though there are times when he points things out, and I don't mind personally because he doesn't interfere and he always does it in a kind way. Plus, I just know he wants the best for me. That doesn't mean I ever listen to him. But I like that he and I have the kind of relationship where you can do that. So if you two have that, you can consider saying hey, how have things been going in your coparenting relationship since he started dating, and anything you wanna talk about? Or some thing non-threatening or judge mental. But also don't hold it against the girlfriend. She's likely navigating this for the first time too. There are bound to be bumps along the way when learning something new.

how do I speak to my son about this? Or am I meddling too much? Do I have reason to be concerned or am I being an over protective mother hen?

Unless this is a hill to die on issue where you honestly feel that your grandchildren are being seriously harmed and you are willing to risk being estranged from your son and his New GF.. you do not speak to him about this.  This is his dynamic to manage.

Look,  too many people confuse "frequent and familiar communication" with good coparenting.  Especially if your son was not in a relationship prior.. he and his EX may have actually gotten into a somewhat unhealthy dynamic of being in too frequent communication.. enmeshed.  What may to you appear to have been "good communication".. may in fact have involved too much involvement in the day to day of each other's household.  Too much familiar communication that was involving things outside the child/parenting arena... it may have also been much more frequent than necessary... but when he wasn't dating anyone.. he didn't have any reason to feel like putting up that boundary.

Good Coparenting does not mean that every aspect of the kid's lives needs to be discussed with both parents.  Certainly, when the children are with your son or with his EX.. each of these parents should be able to feel confident that the other parent "has it under control".. no need to discuss every rule broken or punishment.  

There is literally almost no reason for the parents to be in daily communication regarding the children.  Certainly, multiple calls or texts a day are intrusions onto the other household that cannot possibly rise to the level of urgent need.  Of course, if a decision needs to be made on summer camp.  Or if the child has gotten into trouble at school.. a call or joint conference to make that decision is fine.  A call or text to confirm pickup or drop times/locations (if they aren't set in stone).. or to inform the other parent of a DR appt.. or school event etc.. if they wouldn't know otherwise fine.

But JOINT birthday parties.. NOPE.. shouldn't happen.. joint outings.. vacations.. none of that with the EX.. that is not healthy behavior in almost all situations.

So... do you know how much they used to communicate?  do you know what limits the GF prefers?  I think it's reasonable to expect my partner isn't going to rush to constantly call and text with his EX.. over minor issues that are not urgent.  I also expect each parent to deal with behavior issues in their own home.  Sure.. a report of a troubling behavior trend.. yes.. pass that along. but otherwise.. they are not operating as a joint household any more.

Yea, this is not your place to interject yourself at all.  Don't say anything.  It's reasonable that a significant other would want boundaries in place for communication with the other parent.  

Also, is this really about your son and his ex?  Because the title of your blog makes it sound like you are the BM in the scenario.

"even to acknowledge a text she has sent"

He was expected to acknowledge every single text she sent?!  What's the point in that, other than to keep him busy all day?

By the way, how do you know all this? Who told you? His ex?

That aside, please step back and stay out of it. This is your son's life, not yours. He gets to decide how to run it. 

Do not be that mom OR worse that meddling MIL to a future DIL. 

Maybe the GF is drawing healthy boundaries. Read up on here on how some BM's and MIL's cause so much shit stirring.  Tread carefully. Remember your son is divorced so why do you care how and when he communicates with the BM.  I get you love your son and grandkids. My bet his GF loves him and wants a healthy relationship. 

But then again your username is Queenjean

Talking to there EX.  Or just text and email so they see what being said.  No matter what relationship he enters there is always going to be this type of thing going on    So just stay out of it.  Try to have a good relationship with GF 

This is meddling, and when my MIL meddled too much, my DH just put up more boundaries with her.

Your son is an adult. He knows his life better than you do. His new GF may be totally right or totally wrong, but it's HIS choice in how he chooses to handle it. You can choose to get involved, but be prepared for the consequences.

Family wizard can help. Parents only communicate about the children. 

Maybe she is in a situation like I  was. But I was married and my hubs kids were grown. Ex wife still loved to abuse my hub. The kids wanted them back together.  My hub was conflicted and I took that as he still wanting his ex (mannnny other things). But she was hc.

I don't know if your dil is hc but your son is honorable in wanting to put his new rel. First. ...ESPECIALLY if your son's ex still pines for him.

Ex wives can be a problem in my book if ex hubs throw new gf then wife under the bus n cater to ex wife. For any reason. I know exs can be friends, but for me...I would need to be her friend too. 

Your son sounds mature and like a real man to want to honor his gf. Yes, she may be insecure that his ex  wants him back. Buuut there may be reasons for that.

Family wizard will nip all the extraneous chit chat. Just communicate about the kids visible for the courts to see.

Sometimes, what two divorced people call co-parenting, is really just emotional enmeshment, they just can't seem to break free from each other.

Divorced parents don't have to talk and text about EVERYTHING involving the kids. Yes, there can be too much communication. Yes,there can even be jealousy of the new girlfriend. Not the kind of jealousy that you want him back, but the kind of jealousy that you don't come first, anymore, even though you have his children. It can be a hard fact to be faced with, but it is a fact.

When two divorced people get into new relationships, the new partner's feelings need to be taken into consideration. With a new relationship, sometimes comes the revelation that the "co-parenting" was, in fact, unhealthy enmeshment/dependence.

Him stepping back the communication a bit does not mean he loves his kids any less.

I am worried that she is starting to influence his decision making and how he wishes to cooperatively parent and communicate with his ex wife.

You will just need to come to terms with it.

A question. How would you take it if your son told you how to perpetrate your significant other relationships?  I for one am fully on team.... the mate matters, the X doesnt.  When one or the other Xspouse parent enters into an SO relationship their SO has equal say to how that relationship develops and an equal say on any and all things related to their home and life.  An X gets zero say.  

Your DS can and should set and execute his own parenting model in his home in partnership with his mate. Just as his X should in her home with her mate.

Colaborative parenting is certainly a good idea, but incorporating your X into your future focused life is rarely an good idea IMHO and often is detrimental to the closeness of the new families relationship with the failed family progeny that transition back and forth  between mom's house and dad's house.

IMHO discussion with an X regarding shared children should be limited to health care and school performance... period.

Both parents should be independent enough to care for their kids and make all of the related decisions for themselves and their kids in their home and in the event that they have a mate, partner with their mate in parenting, providing, and managing their lives together and the lives of any children in the home regardless of kid biology.

I would advise that you purge your DS's X from your mind and family. She is no longer family.  She is no longer your concern in any way. Engage with your son, support your son as his mother, and enjoy your relationship with your GK's.  Your time with them comes from their tiem with their father. Not from their time with his X.

Who thinks it's a problem, your son, or his ex? 

"Dads new gf having input on how we coparent"

You are your sons mother, your grand childs grandmother.. there is no "we" to this co-parenting equation. 

If either my mother or the other grandmothers to my children included themselves as you have - I would -with gusto- tell you to go find your dish and lay by it and maybe even with a boot to your ass. 

If you care about you and your sons relationship longevity, I would sincerely think about unsticking the ex from your rump. 

Sincerely,

A new old girlfriend

Ladies and gentlemen, I do believe we have a hit and run here...