It is highly unlikely that you have a future with either one. You are breaking the trust of these women, who may well be making life decisions based on their involvement with you, which is based on a lie. Your actions have consequences, even if you are not the one who has to face them.
Since you obviously don't care about how your actions affect others, feel free to carry on, choose one, both, swap them out for newer models, whatever. The question is, what do you want out of life? You want to play and have fun? That lifestyle comes with its own set of consequences.
My advice is to come clean in as kind and gentle a fashion as you can manage. It probably won't end well, but you will at least be minimizing the damage. Or maybe you'll find out (unlikely as it may be) that one or both are polyamorous, then you may be able to have your cake and eat it too, as long as you are willing to share.