I read your post twice. I'll call your husband Steve, the other man Paul and his wife Sarah.
You and Paul have a codependent relationship. Your emotions steer the relationship you have with Steve. Paul's emotions steer the relationship he has with Sarah.
If the 4 of you formed a quad, the emotions between you and Paul would steer everything. That means Sarah and Steve would be pulled along for the very unpleasant ride between you and Paul.
My guess is Sarah and Steve would bond. They wouldn't do it out of love for each other. They would do it out of the desire to seek emotional shelter from the big waves you and Paul create.
Codependent highs are higher than the highs of healthy relationships, but also very short lived. Codependent lows are much lower than the lows of healthy relationships.
This means codependent emotional waves (comparing to ocean waves) are taller (drama/instability) and move faster than healthy waves. You are attracted to him because he easily moves your emotions.
The quad you want will not work with Paul and Sarah.