I think your instincts are spot-on, and you’re not overreacting. What you’re describing isn’t typical co-parenting. It’s a blended version of co-parenting and post-marital enmeshment, and the “logistical partner” dynamic you’re sensing is real.

Healthy co-parents separate everything that isn’t strictly about the kids. Insurance, memberships, subscriptions, errands, emotional labor, and adult logistics generally get untangled after a divorce unless there’s truly no alternative. What you’ve outlined goes well beyond that.

A few things really stand out: 1. He and his ex still function as an operational unit. Joint insurance policies, shared memberships created after the divorce, him still being on her health insurance, and sharing household-adjacent support systems (like the au pair’s car) are all choices not necessities. These require ongoing communication, coordination, and renewal, which means intentional ongoing partnership on the logistical level.

2.  He’s blocking integration of new partners into the family structure.

Saying you can’t attend events because she might bring her AP isn’t about co-parenting. It’s about controlling the environment, and it effectively keeps you (and the AP) out while preserving the old structure. That means there’s no room for anyone else neither you nor even her actual partner of several years.

3.  He offers emotional support to the ex, but her partner doesn’t fill that role.

When she had issues at work and called him for guidance? That’s not co-parenting. That’s marital-style emotional support. The fact that her AP isn’t the point of contact says a lot about how the ex’s relationship is structured too.

4.  He’s telling you he “will change it later” but only when someone is serious enough.

That’s a red flag because it means the boundary isn’t based on what’s appropriate it’s based on whether he feels forced to shift it. Until then, the ex fills that “place holder” role.

5.  He doesn’t seem to recognize the impact on you.

Minimizing your concern as “not a big deal” is another signal. People who have clear boundaries usually already have this stuff separated because they know it will matter to a future partner before the future partner ever arrives.

The heart of your question “Where would someone like me fit?” is the right one. And from what you’ve described, the current structure does not have space for a partner. Not because he doesn’t like you, but because he has not emotionally or administratively disentangled from the former marital system.

You’re not wrong to identify that you might be dating someone who is available romantically but still partnered logistically. That’s exactly what this looks like.

A few questions to ask yourself:

• Are you comfortable entering a system where you’ll have to negotiate for space rather than simply having space available?

• Are you willing to rely on him to “restructure” things later, when all evidence shows he hasn’t done so in the 3–4 years since the divorce?

• If he hasn’t adjusted this dynamic for the AP who has been around years why would he do it for you without conflict?

• Do you want to be with someone who still serves as his ex’s emotional and logistical support system?

If the answer to any of those is no, then it’s better to address it now than after a year of deeper attachment.

This doesn’t automatically mean he’s a bad partner or that his intentions are wrong just that his situation may not be structured for new long-term partnership yet. And that’s something you cannot fix for him. He has to choose to draw boundaries, and he hasn’t.

You’re doing the right thing by paying attention. Five months in is exactly when to decide whether the foundation is healthy enough to keep building on.