So, I recently entered a relationship with two wonderful married people. This isn't a unicorn hunter situation; we're taking lots of steps to ensure that everything is ethical and fair. One of them is a trans guy, so he's my boyfriend, but the other person is nonbinary. For a while, even when we weren't dating, we have been trying to figure out a good, gender-neutral term for them. They don't like the term partner, as it doesn't convey a romantic relationship inherently to them and seems more like a business partner to them. I don't like SO because it implies monogamy to me, and other half is obviously not even a consideration. Everything else we've found is cheesy, awkward to say, or doesn't inherently imply a romantic connection, which is important because having to clarify what I mean every time is time-consuming and we both feel like I shouldn't have to do that. So I thought I'd ask here for some ideas.