Hi and welcome!
I don't have any advice to share, since I have never been in any kind of similar arrangement myself - but it does sound to me like you are all in pretty good shape. Of course it's confusing! This is a totally new situation for all of you, and there are no instruction manuals! I would hazard a guess that the jealousy and insecurties, etc. are coming to the fore because everything is now in the open. Prior to that, things were going on unspoken, so it was easier to hide those difficult feelings along with the attractions, and not let them rise to the surface.
I recommend doing some reading. Opening Up by Tristan Taormino is a good one. You may also like Polyamory in the 21st Century by Deborah Anapol. And check out our Golden Nuggets forum here for other resources.
The world opens up... when you do.
Oh, oh, can't you see? Love is the drug for me. ~Bryan Ferry
"Love is that condition in which another person's happiness is essential to your own." ~Robert Heinlein