You said you are addicted to them. So do you actually feel addicted or was that a playful expression?
I suppose the farther we go in different things, it adds more stimulation. Maybe over stimulation. Don't burn yourself out! If making love to one woman seems boring. I would cool off with it a little!
I've never experienced what you have. All I can say is that I think you must be having some extra fun! I often heard that threesomes will wreck a serious relationship. I really don't have anything else to add! Good luck!