Looking for advice on boundaries in a blended family

Hi everyone,

I'm looking for advice from other stepparents who have a genuinely positive relationship with their partner's ex.

My boyfriend (38M) has an 8-year-old son, and over the last year or so we've slowly built what feels like a really healthy dynamic.

We intentionally took things slowly. My partner and I talked early on about expectations, and I was clear that I wasn't trying to replace anyone. I met BM before I met SS, and only met him after we'd been together for about a year. Since then, SS and I have built our own relationship. He'll occasionally call me "Mom" or "Stepmom," and if he says "Mom," I gently remind him that he already has one.

These days we have sleepovers when he's with us, and sometimes all four of us even have family game days together. BM and I have also become friends.

Here's where I'm starting to question myself.

BM doesn't have much family nearby or many close friends. Because of that, I've naturally started including her in my own support system. She's met my parents, some of my friends, and I've genuinely wanted her to feel welcome because I know having healthy adults around ultimately benefits SS.

I recently had a conversation with my mom and another family friend, and they both cautioned me that:

- BM's emotional support system isn't my responsibility.

- Things may be peaceful now, but that doesn't mean they'll always stay that way.

- I should be careful not to build my life around my partner's existing family.

- My partner's son will (and should) always be his priority.

I don't disagree with any of that, but it did make me wonder whether I'm blurring boundaries without realizing it.

For those of you who have a good relationship with BM:

- How close is too close?

- Have you found boundaries that help protect everyone involved?

- Have you ever had to pull back after realizing you were overextending yourself?

- Is there anything you wish you'd done differently early on?

I'm grateful that things are peaceful, and I don't want to create problems where there aren't any. I just want to make sure I'm building healthy, sustainable relationships for the long term rather than acting purely out of empathy.