WIBU to message his new girlfriend telling her he has a child?

[CarsCary]

Background first, my ex and I were together for 6 years and engaged. We had a generally good relationship. We now have a 8 month old son together, he has never met him but does pay maintenance.
The reason he has never met his son is because about this time last year he got offered a job in London, massive pay rise included but I couldn’t move, I care for my mum and dad who are both very ill and I am responsible for my younger brother who has additional needs. He is able to live independently but needs support with this.
Anyway we broke up and in January he moved to London, our son was born in February. He blocked me everywhere. I was able to have a short conversation with him when our son was born through a mutual friend, he said he would pay child maintenance, sent me the calculation from the government calculator and said he’d pay £50 per month over this. He then said he did not want to go on the birth certificate and he wouldn’t be involved.
This broke my heart, I never wanted my son to grow up without a dad, I’ve been really struggling with everything but I get up each day for my son and my family and get on with it.
At the weekend I went to a friends wedding and ran into an old mutual friend of my ex and I. We were chatting and a little drunk when she told me she still follows him if I want to have a little stalk of his instagram. I should have probably said no but I was tipsy and curiosity got the better of me.
He has a new girlfriend, her instagram is public. They must have started dating around march/April but seeing all the posts made me irrationally angry. He’s been off to New York, Paris, Rhodes, Amsterdam, Berlin etc. with her while I’ve been crying at home caring for OUR son alone. I know this stupid but I’m also angry as it feels like he’s got off easy, he broke my heart, he abandoned his son and now he’s dating some gorgeous girl, who’s got pics on her instagram of her modelling. He’s going out for dinner to lovely restaurants and taking nice holidays and me who did nothing wrong and our son who has done nothing wrong just get by every month!
Now I’m willing to bet she has no idea he has a son and I want to tell her, I know he will just tell her I’m crazy or something but I feel like I should tell her anyway. Her account is public so I could message her easily and I’m sure it would go to requests but AIBU to want to do this? Should I just focus on our gorgeous boy and moving on?

Think hard about why you want to tell the new girlfriend. Realistically it's either to spoil their relationship, or force contact with your son.
You will not be privy to the impact on their relationship, he could twist it any way he likes. Probably say you tricked him etc
Contact? Sounds messy and not in your sons interest, if his dad has to be forced in this way.
Live your best life op. Sort the debt out, ensure you have a nice home for you and your son and fill both your lives with the friends and family who love you.

I won’t message her.
As many posters have said it will just rock the boat, while this isn’t what I wanted my son has stability and all the love her could ever need, I don’t want to be petty and ruin that.
If I’m honest I stalked a little more instagram, her TikTok etc.
It seems like he’s bought a flat based on one of the TikTok’s which has made me more resentful as I’m in a rented terrace and we were going to buy together now my son will likely never have that security. I also know his mum would be disgusted he’s spending her money on holidays and not his child.
I don’t feel any resentment towards the girl, if anything I pity her and feel sorry for her.
Im sure I’ll sit bitter and annoyed for a few more days but eventually I’ll get over this like I have everything else.

He asked not to be put on the birth certificate? Did you? Can you retrospectively? It just seems so wrong that it’s not documented.

You have absolutely NOTHING to be gained by messaging her.

Keep living your life and look after your DC. You have a ex P who pays for his child, which is more than most. Live your best life

He pays £1,000 (£50 more than CMS calculator). I think she should leave it for now.

We weren’t married so I couldn’t put him on it without him present, it was clear he wasn’t going to show.

You say that he decided to apply for the job and move when you were pregnant. Is this the case and if so was this a planned pregnancy and then part way through he changed his mind? Or did he decide to apply, you didn’t want to go and then you found yourself pregnant and hoped it would change his plans?

@CarsCary Just to throw something else into the mix, cm isn't taken into account for benefits, have you checked to see if you are eligible for universal credit- I'd be surprised with your income and rent and childcare to cover if you aren't eligible. It might just make the difference if he ever does stop paying and you do need to go vis CMS

Yes you would be totally unreasonable.

If they weren’t married, he had to be there in person to be included so he can unfortunately refuse. If they were married she could have put him on there. CMS would be able to do a paternity test if she went down that route one day and he challenged it.

Please tell her. I'd want to know. I'd never want to be in a relationship with a man who ignores his own child.

And open a formal CMS case. Take the control away from him.

I found out I was pregnant before he applied for the job. It wasn’t planned, I was on the pill. In the same year he inherited a large amount of money and met someone who had worked at his company moved to London and was earning a lot more which piqued his interest. He wasn’t trapped but circumstances did change.

Telling her will bring you nothing but aggro. I’m glad you’ve decided not to.

RTWT

You can do what suits you, OP. But it won't change anything. You might get a moment's sense of satisfaction but it will only be a moment. If it splits them up - and it probably won't - what then? Is he going to come back?

Just live your life. Enjoy it. Don't look backwards. Look forwards and build your life as best you can.

Don't do it op. You would be doing it for revenge and the payoff won't be worth it. Instead enjoy the benefits of not having a him interfering in how you raise your child.

Look after your own interests first. If he's paying up regularly then don't rock the boat.

Better to have regular voluntary payments from a cooperative father than putting your faith in the CMS to extract money from a pissed off one.

Agreed. If you message her, the first thing he’ll likely do is stop your payments. Then you won’t be able to pay your rent.

In a strong believer of women looking out for women, but in this situation I'm not sure it would achieve anything. .....I just wanted to post to let you know that while it feels hes winning with the holidays and the free life he's living, he really isn't. Your in the trenches right now but the love you'll feel from your son will 100% trump any experiences he's having right now. You will always have the love of your son and he has thrown that away, id honestly feel sorry for him rather than envious. You sound like you are doing a fantastic job with all that you are facing at the moment, just keep doing you and forget about this twat ❤️

Why poke the bear? Seriously him out of your life and 1k in your pocket? Why would you initiate contact with anyone in his life??

Well done OP. What a difficult situation you're in. You sound to be a lovely person and you've enough on your plate without getting involved in this additional drama.

Hope the thread's been useful to you? Please don't feel obliged to respond to people making nasty suggestions / implications about your motivations. You've been very clear in your posts about what's happened.
Good luck with everything

I totally sympathise @CarsCary. Men like this are infuriating. I have not exactly the same situation but my ex left me when I was pregnant and even ended up getting married only 6 months after our baby was born and he acts like he doesn't have a child at all and it makes me so mad. His wife does know but probably only halve truths. I knew his family well and when he left me pregnant for the OW I told everyone who reached out to me (including some of the OW's family!). Think he/they were hoping to keep it a secret to make themselves not look so bad. We are in contact but he's never met his son even though sometimes he claims he wants full custody (very odd).

So anyway yes I would tell her as a PP said I'd want to know if I was her and I'd dump him (maybe she wouldn't but who cares) and your son deserves not to be a secret. It probably won't change anything that his worthless dad does though I'm sorry to say...

The only thing is sounds like he could afford to pay more CM so have you looked into this?

If it were me, I don't think I'd antagonise such a callous man. Honestly if he's capable of abandoning his Child who know what else he's capable of. While you're not wrong to let this women know so she stops wasting her time, you're just opening yourself to abuse

It always drives me mad women saying don't sent the message. Women need to look out for women, if we all called out this behaviour and gave each other the heads up then it would be harder for these ment to treat us like this with the risk future women will know the truth. That said I'd maybe wait until you have gone via CMS so he can't punish you be withholding money

No its £50 over what the CMS calculator said.