Isn't life interesting?!! Good for you! It sounds like all four of you have been willing to do the work relationships require, admit to mistakes, and pick each other up when someone stumbles.
I do have a question. You mentioned physical intimacy had to be toned down and then worked up to again slowly. Has it reached equilibrium? Are you all free to be sexual with whichever partner you wish, and as freely as desired, without insecurities or incriminations surfacing? Or are there certain things still not allowed, or specific rules in place about sharing yourselves sexually with each other?
I've always been curious about quads. There are a few other members here who have been involved successfully in quads over time. There are some threads with their stories here, if you do a search. Thanks for sharing yours with us.