Yes, there is a "median".
You both need to date people individually. That's just all there is to it. Even though you said that is not an option for you. It really is very important that you not allow your relationship with other people to eclipse your relationship with yourself. Part of that is being an individual in ALL of your relationships, romantic/sexual or otherwise.
EVEN THOUGH YOU SAID IT'S NOT AN OPTION.
You know how they say that insanity is trying the same thing over and over but expecting different results?
If you can't deal with the personal growth and responsibilities that go with it at this time, that is ok. It's all part of the journey. But, when you come here and ask people what they think you "should" do, you may get some answers that are not what you want to hear.
This is not to say that it is IMPOSSIBLE you will find someone you both "click" with and can live happily ever after. But you should not have that as a goal as you go about meeting new people and cultivating relationships.
If it is crucial that you only socialize as a couple, then you're prob'ly better off sticking with swinging "scenes" where there are taboos against becoming emotionally involved with your sex partner(s).
Finally, consider that if you and your partner both want drastically different interactions with others outside of your "primary" relationship, you may be fundamentally incompatible in the grand scheme of things. Not only do people change (i'm gonna be blatantly age-ist here - you are both at the age where you have some experience but are just starting to get in touch with who you really are and where you really want your life to go from here), but they start to realize certain things about who they were all along but never quite understood before.
So you have to get very honest with yourself about certain things you may not even want to admit exist.