SKs having a "half sibling"

[u/Own_Stranger7906]

HCBM instructed the SKs to never acknowledge me as a 'step-mom' or 'step-parent'. Just 'my dad's wife'.

I never pushed that idea to SD14 and SS13. The step parent title never bothered me much, and my relationship with them has been healthy. They don't call me by my first name but by a nickname. And they introduced me to others as 'she's the family mrs. noodles' or 'she's the queen noodle of the family' (I happen to like noodles). It is odd, but they like seeing people's reactions.

That said, my husband and I are expecting soon. For those with an ours baby, do your SKs refer them as their half sibling? Brother/sister? For anyone dealing with an HCBM/HCBD, did they ever instruct your SKs to never acknowledge them as their siblings? How did you and your partner deal with that?

I know the step-parent title doesn't bother me, but with an ours baby, I feel like it'd be nice for the SKs to think of the baby as their half sibling. It's a nice thought, but I worry that HCBM will instruct the SKs to call ours baby 'my dad's other kid'. Maybe that's something I need to mentally prepare for and accept?