This is definitely something sl needs, there are tons of people in sl with non-traditional relationships. Myself included.

Hello, and thank you for your feature request regarding the ability to display multiple partners in Second Life. This idea was actually brought up by another resident in the past, and we are merging your comments to get to it faster. We understand that this feature is important to many in the community who are in polyamorous relationships, and we appreciate your input. While we have no estimate on when it may be implemented, please keep an eye on future updates. Your suggestions are invaluable in helping us improve Second Life. Thank you for your continued commitment and for sharing your ideas!