I’m poly and me and a friend really want to date but they don’t want to have a sister wife feeling and, really, I don’t want to either? What should we do?

In this situation, it sounds like clarity is key. You two need to define for yourselves and for each other what you mean by a “sister wife feeling,” and what about that you don’t want. Is it that you worry about creating a life that’s too insular? Are you concerned about codependence, or the challenge of finding friends and partners outside each other? Are you worried about how others see you? What, specifically, is this “sister wife feeling” that you don’t want to have?

Identify what your “worst case scenario” is, beyond a quick phrase, then come up with a plan to avoid it. Maybe there are non-dating friendships you two want to make sure you continue to cultivate, and you’ll make a concerted effort to keep those people in your lives and not be too much in your friend-partner bubble when you’re around them. Maybe there are aspects of your friendship you two don’t want to bring into a dating relationship, and you need to talk about that and re-draw your boundaries accordingly. 

In all honesty, a concern about poly partners being too close, or too “sisterly,” is perhaps one of the better problems to have. Be grateful for the opportunity to explore a new avenue of your relationship, stay self-aware and honest with each other, and enjoy!