Wwyd re ex seeing dc and mixing households?

[WednesdayAllDay]

Partner and I separated over a year ago. Our dc go to see him twice a week.

The last two times the dc have come back and told me they've been in someone else's home for dinner/play.
One is his new partners' home with her dc.
The other is a friend of my ex with his two dc.

I can assure you there is no jealousy on my part, I want my ex to move on and as long as my dc are happy, I'm happy.
I've mentioned previously I don't want our dc mixing indoors with other families but he's not listening.

Wwyd? Leave him to do as he wishes when he has the dc or out your foot down?

I’d say something. Ok if he’s a single adult he’s allowed a bubble which could be his new partner’s household but shouldn’t be going in anyone else’s house. Given the current situation the more people keep behaving like this the longer we’re going to be in lockdown and restrictions and ultimately the risk of them mixing with other households is being passed on to you. Quite frankly I’m done with people like him flexing / ignoring the rules!!

Thanks @emmathedilemma

I did say to him at the weekend I don't want the dc mixing but he's completely ignored me again.