My Open Relationship Experiment Went Too Well - Seeking Advice

So here’s the thing. I’m Alex, a software engineer who’s been in an open relationship with my partner, Jamie, for almost two years now. We both agreed that being non-monogamous would work best for us because of our different interests and how we want to experience life. It started off well; it was just like adding another friend to our friendship group. No big deal. The twist came a few weeks ago when I met someone at a tech meetup, named Mia. She’s smart, funny, and surprisingly into my work, which is rare! We hit it off really quickly and after a couple of conversations, we decided to explore this thing between us in a more physical way. Fast forward a month later, and I’ve found myself deeply emotionally connected with Mia while still feeling very close to Jamie. Now here’s where things get messy. Recently, Jamie confessed they felt jealous about the time I spend with Mia and want me to choose between them or take a break from seeing Mia for a bit. The funny thing is, Jamie used to be totally fine with my non-monogamy. Now it seems like they're questioning everything. I care about both of these women deeply, but emotionally speaking, Mia’s made a big impact on me and I don’t want to let her go. Does that mean I should prioritize one relationship over the other? Or is there another way we can work through this where everyone feels respected? What do you think? Should I have Jamie talk things out with Mia or find another solution altogether? Your thoughts are greatly appreciated.