The notable thing is that some partners don't want to know what's going on with the other partners. Some people are very private and don't like to share a lot. But if you are getting drawn into the middle of things and it affects you in that way, you certainly have a right to know, or to at least ask.
I guess it depends what/how much detail we're talking about. Details of sexual encounters can be very private for some people. But if you are just trying to find out what is amiss between your two companions, that is somewhat different.
Having said all that, it's really ultimately different for each little poly group. Some groups share a lot with each other, some only share a minimal amount of information. Some can only handle a small amount of information. If you feel you could handle the information, it seems fair to let you try.
Just remember that sometimes one partner might share something about another partner, and it might seem to be something extremely upsetting, but it might actually just be venting, and something they can work out on their own easily enough. Some partners share about their other partners because they need to vent. So, if someone tells you some bad news, it may or may not be something you need to do anything about, and they may not need or want any suggestions, just a listening ear. It is a fine line to walk.
If you feel concerned about what's going on with your companions, you might even want to do a three-person sit-down, express your concerns, and try to get some things out on the table. However you're getting pulled into the middle of their conflicts, you want to try to get pulled into that less if possible. Perhaps knowing what's going on would enable you to keep yourself disentangled.
These are just some thoughts; what's right for you is probably unique to the three of you. I don't see any harm in asking them. Just so you know it's not guaranteed you'd get an answer. You can only try.
Love means never having to say, "Put down that meat cleaver!"