My boyfriend’s friendship with his ex- Is this something to worry about?

My (47F) boyfriend (41M) of 6 years has a close friendship with his ex who is married with kids. How should I deal with my insecurities surrounding their relationship?

I’ve been with my boyfriend for almost 6 years, both have been married with children from those marriages. We have a great relationship, families and kids all get along and have absolutely no reason to feel like there should be any cause for concern. However, I just can’t shake this feeling of uncertainly when it comes to his friendship with a group he’s known since high school- so dated way back to 20+ years ago.

As far as I know, they all keep in touch via group chat and still have a close bond, even though they only see each other maybe once or twice a year during special occasions. Specifically, it is two couples. One couple who lives about 10 miles from me. Boyfriend lives about 60 miles from me so since he was at my place this weekend, it just happened to be during a weekend this couple planned a party for one of their kids.

Last time my BF saw everyone was close to a year ago, for another birthday party they hosted. BF invited me and my kids and it was the first time I had ever met them. Another married couple with their kids was there and the woman happened to be my BFs ex from close to 20 years ago. I know it’s so long ago but seeing how close knit the two couples are with my BF and me feeling somewhat excluded only heightened my insecurities. I don’t think my BF even remembered a few years back when he mentioned in passing about these friends and she was an ex, now married. I remembered the names so I knew in the back of my mind they were together. She was so drunk, giddy, loud, very up close and personal talking to my BF, just catching up. Seemed innocent but the group were reminiscing about the past and made it so clear how very tight they all were.

Forward to last night, the couple hosted another party and my BF and I went, just the two of us with the kids since we didn’t have them. Same two couples there and the ex kept talking to my BF, obviously very drunk, loud, laughing, smacking his knee, just asking him to update her on everything about work, family, their other friends, etc.

Later on, she started talking to me and said how they go way back with my BF and they all have the closest bond, and “whatever I want to happen, just tell them and they’ll make it happen”… whatever that means. How she sees how my BF looks at me and he must really love me because she knows him so well. Again, she’s intoxicated and has only met me twice. Then starts hinting saying there is a lot of “overlap” in their relationships- her words. I asked what she meant and she said many years ago, her now husband was at some point, with my BF’s ex wife. Then she specifically mentions herself, my BF, the others… have this overlap. Without straight up saying she was with my BF. I feel like she was intentionally trying to make me aware of that makes sense? Then smiles, hugs me, laughs and says I’m sorry I know it’s weird hahaha!

I know they all chat whether it be a group text to invite people over for an event, maybe sharing photos of the past, greeting each other on holidays, etc. and I’ve even seen just her name pop up on my boyfriends phone sending him a text. It was on New Year’s so I’m guessing it was greeting him. But I don’t know if my feelings of discomfort are valid or if I’m just driving myself crazy over this when I should be. What does everyone think?