I just feel so sad for DS

No advice but you sound like a great mum ❤️

Your poor son. You are obviously trying to be fair to everyone but your son is your main priority. You can't promise your ex that your DS will react as he wants but repeating, as you have done here, what a great relationship they used to have might remind him what the child has lost. Perhaps you haven't told your ex how sad your DS has been since he moved away (and he would probably blame you for trying to make him feel guilty)? I don't think everyone can be happy here, sorry.

YANBU.
Your ds has every right to be upset. His dad is moving on and your ds feels pushed out. He is a child and him being upset is natural.

All you can do is emphasise that you have his back completely, listen to his worries, be there for him, love him, reassure him that his life with you is stable and safe.

ExP & woman are being self-centered and their behavior is baffling.

Can they not put themselves in DS shoes?

Never is child is “happy” that their dad is having a new baby with another family. It’s always a conflicted situation. Dad is moving on without me….. cannot believe they thought he would be jumping w joy, sexist too, a girl might be excited about a baby … less likely boy going to be that interested in an infant & mysteries of childbirth.

It almost seems like they are using this situation to break the already thin ties with DS and you. Like, they have no time now for DS, will have NO time when new baby arrives.

Really selfish & sad.

What's your DS relationship with your ex's side of the family like?
Is there any other adult males on that side of the family?

Your poor DS. His dad is a total total twat. It’s good that he has you to rely on…. I do feel for him. I hope is okay, with lots of love and support.

Yes, he sounds like the 10 year old. I'm also reminded of the David Brent scene in The Office where he announces redundancies and adds that it's good news for him though as it means a promotion. It's that level of sensitivity from your ex.

It’s so upsetting that men are capable of detaching themselves from their children, once a new opportunity comes along to build a relationship and new family unit. It happens all the time. They really are emotionally stunted twats. Unfortunately there’s nothing you can do. He will just dig his heels in and not take responsibility for anything he has done. All you can do is be there for your ds when he’s upset, and try to maybe enrol a male role model to be there for him too, such as a member of your family - brother or similar.

Oh your poor little boy! Sadly this is a tale as old as time - family number 2 with New Woman and New Baby tales precedent and your son will notice. And I have never know family number 2 to approach any of it with sensitivity.

I hate to say it, and I wish I was saying different, but you have years of heartache so I think you should consider now how to navigate it. Try not to slag exH off no matter how tempting but always validate your son’s feelings.

The thing is about preteens is that, even if you hadn’t divorced your ex, in 2-3 years time he’s gonna wanna spend less time at home and more with friends, so it may be a natural flow away from his dad anyway (hopefully you won’t be blamed like my friend currently is because he 12yo doesn’t wanna travel 3 hours every Friday she w ants to see her pals).

Your DS has every right to feel completely let down and pissed off. Telling him this should help him worry less about his own feelings and anxiety. He’s at a delicate age pre -teen. Validating his feelings is the best thing you can do. No need to sugar coat your ex’s decisions.

Your ex needs to grow the hell up

I feel so sorry for your son.
His dad literally picked a girlfriend over him and moved away.
Not a job. Not a necessity. A girlfriend.
And suddenly a baby.

And he's annoyed son isn't jumping for joy? WTF. Son can see himself being pushed out of his life.

Your ExP sounds very selfish. Your DS is allowed to feel however he likes over the situation. You were awesome in standing up for your DS as he was unfairly put on the spot.

I would wager that guilt and fear are driving your exp reaction.

I think he probably feels guilty about moving on/ away and maybe scared about the new baby's arrival, and it's coming out as anger projected at your son, because his reaction confirms your exp worst fears. No one wants their child to feel rejected by them. It's not a sign of good parenting. His ego is stopping him from accepting your son's reaction. He needs to grow up and put his son first. That's my take on it anyway.

your ex is a selfish pig! Did he ask you if you were able to pick up all school runs and clubs etc mid week?

how is planning weekend contact? To stay in the area every other weekend?

my ex moved 2 hours away when my son was very young and discussed nothing with me so I’ve had to do everything alone as well as working full time and relying on other parents, it’s not easy. He comes up every other weekend and stays local with family and I have nothing to do with the driving etc.

Our son is mid teens now so sometimes he tells him not to bother coming up but he’s never done a school run or clubs etc.

i imagine once the baby comes he won’t be up every weekend.

So your ex thinks your son should be happy that he's being left behind while ex starts a new family? Or pretend?

No. Surpressing his feelings about how his dad went from seeing him every day and being included in his life to limited contact with even less in the future is not emotionally healthy. It's pretty normal to resent new sibs initially in the same family.

Your son might need to talk to a therapist about his feelings and how to adjust to such a big change in his life and how to deal with negative feelings.

Your ex is being unrealistic here. He wants your son to put on a happy face so he doesn't have to feel guilty that he put new woman ahead of his child. I'm sorry your son is having to deal with this.

I think your DS is lucky to have you as his mum, advocating for him, understanding his emotions and doing the best you can to facilitate a good relationship with his dad. You sound like a really fab mum.

Your son's dad, however... Getting annoyed that a 10yo wasn't happy about a new baby - how incredibly, incredibly immature of him. YANBU to be sad for your son - it is sad.

In what world does anyone think a 10yr old that has been frankly dumped by his father for a new bit of skirt is responsible for his father's emotional health?

He is being really immature to only consider things from his side, the more he blames his eldest the more it's clear he knows he has been shit but doesn't want to suffer any consequences, he is awful.

I would get your boy into therapy, he will need to talk to someone about this and his abandonment.

You did the right thing by validating your sons emotions, shame on his father and new partner.

This is what I would explain to ExP. Add that obviously you and he will your upmost to ensure DS feels supported through it all, but to a large extent the circumstances will be very hard on him regardless. Any extra efforts he can make to ensure DS sees him prioritising their father-son relationship will probably go a long way to making sure DS doesn't feel pushed out.

I would reassure him (despite feeling that you want to punch him) that you will doing all you can to encourage DS to think of this sibling as a wonderful new family member rather than someone taking his dad away, but that he as dad must remember that HE has the biggest say in how DS feels about it all. That DS has already taken the move hard (probably harder than dad realises) and needs time to catch up on just how much he misses having his dad in his life on a daily basis.

Basically dad has had his head in the sand about the effect on DS. You are the only person who can set him straight, but it's a very hard thing to do without sounding blaming and making him defensive. I think its worth having a go at for DS's sake as he's obviously a man who does/did value his relationship with his son highly.

Sorry I was confused by you saying
*I think DS will come round and ultimately love having a baby around.…” implying he needed to come round from his wrong thinking

also
in an ideal world he would be excited about a new baby..
That world doesn’t exist not even when a couple with one child that are still together have a new baby. It’s very common for the first time a child experiences a younger sibling being born to have negative feelings and worries about it.

I can see you want him to be happy, but it is ok for him to be sad for a good reason like this. His happiness doesn’t depend on being excited or happy for his Dad.

Jesus this man has the sensitivity of an onion, your poor son.
Thank God he has you to advocate for him, don't stop even if your Ex chucks a tantrum

Your ex and the new girlfriend are a pair of selfish twats. The ex should concentrate on being a decent father to his current child rather than having a new baby with someone he barely knows.