I want to be part of their relationship as much as possible... Yes, I like hearing about J from Ian, what he likes about her, etc. It can be physical, emotional, or an action (he liked when she said/did X...). It makes me feel like I'm part of it, involved, trusted.
I wouldn't go and ask about it, though. I just very much enjoy when Raga just can't help but talk about how wonderful she is
I also like talking about my partners with one another so I'm assuming it's also good for him to be able to share.
I'd also like to talk about our common partner with my metamours, if I had any. It's a level of sharing... Being able to talk about how wonderful someone is with a person who feels the exact same way... Share things you love about them... Possibly discover differences in what aspects you like, etc. I'm looking very much forward to it.