Millennial approaching 40 here: I still often refer to my wife as partner, just like before we were married. To me, “bf/gf” represented a title whereas “partner” represents what we are. We are a partnership pursuing goals together, rather than just at the same time. We share the weights of life so that neither one of us has to carry too much. We function together as a singular unit, so we are a net 50/50 partnership. Also, it’s a neutral term that engenders inclusion, and that’s always a boon.