My partner is struggling because my other partner shares the same social circles
I have two partners, Ash and Birch. Me and Ash have been together for 8 years, we live together and have a child. I have been with Birch for 2 years.
When I started seeing Birch, he and Ash knew each other vaguely, but didn't run into each other very often. Since then our social circles have shifted and they go to many same events and share many friends.
Unfortunately Ash is struggling with this a lot. He says he'd rather have a parallel situation where he doesn't have to ever see his meta. He has asked me to ask Birch to not go to all the same events, but that doesn't seem right to me and I have not done that - besides, I can't control where Birch goes.
Ash has become very anxious about this and complains to me that he doesn't have any "safe" social spaces anymore. Trying to discuss where this anxiety comes from has not been fruitful. As far as I know, Birch has been neutral or friendly towards him when they have had interactions.
Any advice? I have a lot of sympathy for Ash's anxiety, but I have no idea what I could do. I can't turn this parallel and because of childcare duties, I'm often not even present when these situations happen so I can't help him there.