He doesn’t want to tell his kids

My fiancé has two daughters, 10 and 12. I’m currently pregnant with my first (his third) child.

Due to custody issues he wasn’t able to see them for a while but now he gets them 50% of the time.

He keeps putting off telling them that I’m pregnant. He’s afraid that they might get jealous or that the baby will take attention away from them. So we’re keeping my pregnancy a secret.

I wanted to do a gender reveal and have them involved considering they’re the big sisters. I thought it would be a cute first bonding experience. But that’s hard to do if they can’t know that I’m pregnant.

I’m also not allowed to buy any baby stuff yet because they would see it and figure it out. I even have to hide my prenatal vitamins.

I think this is horrible. They’re going to find out sooner or later. And I think they will feel betrayed if they figure it out on their own.

The best part is: They already have two younger siblings from their mom. So they’re not new to the whole concept.

I don’t know what to do. My fiancé keeps saying they’re his kids so it’s his decision. And that there’s still plenty of time. I’m 14 weeks, baby is due in December.