Well are you truly poly? Reasoning if it’s fine or not doesn’t matter..but rather asking yourself: will it work?
Because in the end in order for this to work you need a lot of open conversations with every partner to see if this poly thing even works.
Just because you are poly doesn’t mean your partners will be fine with poly relationships.
If it works though it works… it just tends to not get appreciated in legal terms often.. i mean poly marriages are still a rare thing.