>>If the step kid had a birthday when with their actual mother should / would the half sibling be invited. No course they wouldn’t and shouldn’t be. The breakdown of the relationship has created 2 family dynamics. That is now life. The half sibling is not included therefore excluded from events step kid does with his mum but that’s fine. Just have to make sure step kid is spoilt because his parents split.
This post illustrates EXACTLY what it feels like to be a step kid. You might innocently attend someone’s birthday party - maybe because someone offered you the chance, maybe because you wanted to go in order to help honor your (step)family member - having ZERO idea of the vast amount of resentment and symbolism triggered by your presence! And lo, because you showed up at this event, you’re “spoiled."
About 10 years ago I attended a wedding of my step cousin’s, several states away. The airline tickets for me and my husband and kid were > $2000. But I wanted to go to show support and respect to my extended step family who were always, mostly, wonderful to me. My half sister (their blood relative) backed out of coming at the last minute due to some issues with her alcohol use (my mom paid for her hotel room, which sat empty). I thought, well, at least I was there to represent our part of the family at the wedding, even if my half-sister didn't show up.
At the wedding dinner, I made a praising comment to the bride’s sister (another step cousin) and another relative (a third step-cousin), who was one of the few people who were not particualry nice to me. I said, “I’m proud to be related to you folks.” And her response was, “Well, TryingToBeLogical, we’re not actually related.” I suppose that is true, but it was an unkind and unnecessary comment in response to a compliment. Shocked silence all around the table.
Guess she didn't want me there, even though I came to show respect, not grab double privileges. (my step-cousin the bride, and my step-aunt and uncle, were all lovely and welcoming tho).
Haven’t felt the same about them all since. And I keep my own kid away from that step cousin. No need for my kid to be treated rudely because 50 years ago someone got a divorce and now she doesn’t have the “right” grandfather (and is therefore a spoiled interloper).