Should we cancel the shared birthday for my son?

My son is in first grade and hasn’t quite found his place yet when it comes to making friends. He plays “with everyone and no one,” but doesn’t have a close friend he spends a lot of time with.

We’ve been proactive about setting up playdates and inviting kids over, but the invitations rarely get reciprocated. Still, we’ve continued inviting the kids he wants to have over. One of these boys happens to share the same birthday as my son. His parents suggested we combine their birthday celebrations, and we agreed. My son was thrilled with the idea.

A little later, the same parents asked if we could include a third boy in the joint party, even though his birthday isn’t anywhere near the same time. My son was okay with it, so we agreed. These two boys are best friends and often spend time together outside school.

Here’s the problem: my son is never included when these two boys hang out. Despite our multiple invitations to them, it’s “never a good time,” and they don’t suggest alternative dates. This week, my son told us he no longer wants to have a joint party because these boys don’t play with him at school or during after-school care. He’s now feeling really upset about the whole situation.

I’m torn. On one hand, I want to encourage him to go through with it—it could end up being better than we expect. If it doesn’t, we’ll know not to try this again. On the other hand, I completely understand how hard it is for him to celebrate his birthday with two kids who are clearly best friends while he feels left out.

To add to my doubts, I can’t help but feel that the mom of the boy we first spoke to was eager to involve her son’s best friend just so her child wouldn’t have to celebrate “only” with my son. After all, this other boy’s birthday isn’t even in the same month.

Both moms seem super enthusiastic about the shared party, saying it’s a great way for the boys to bond as a trio. But if that’s the case, why don’t they ever include my son in anything? It’s starting to feel like they’re more interested in saving money and effort since I’ve already arranged the venue, food, and decorations, making it much cheaper split three ways.

How would you handle this? Am I overreacting, or is there something off about the way these parents are acting?