To tell his parents that I’m pregnant?

[ReiofHope]

Very long story short
My (ex) partner and I have a 17 month old son. Last August I decided my son and I would live separate from his father as our relationship was becoming toxic.
Things were going well until January when I discovered I am pregnant again.
He was less than thrilled and his attitude has me done with our “relationship”. Of course he can still be in the lives of his children.
I’m now 15 weeks and he’s not mentioned anything to his parents.

My question is when is it reasonable for me to be the one to tell his parents that I am having another baby by their son?
His parents are heavily involved with our first and are wonderful grandparents.

@peperethecat It makes me so furious that careful, responsible, committed couples can suffer from infertility and pregnancy loss whereas people who can't even provide a decent, stable upbringing for the children they've already got just "fall pregnant" and keep having babies.

Excuse me!?!?! WHO said anything about an unstable upbringing? Just because OP had effectively become a single parent?! So you're saying that having a single parent is not a stable upbringing? How VERY DARE you??????? Reported

@peperethecat People like the OP are casually bringing children into totally unsuitable home lives

Since when was being a single parent (a responsible one who removed the toxic person from the child's life!!!!!) a 'totally unsuitable home life???'

How f'ing DARE you?!?!

Given your appalling attitude problem, I'd wager that I give my child a damn sight more stable an upbringing than you give yours. How can you possibly imply that all single parents are unsuitable and unstable?

Your words are excruciatingly painful and offensive. Think about what you're saying please