I have been thrown off by this in multiple conversations. The worst example: I thought someone's trans spouse was cheating with a non-binary person for about a year, before learning the spouse was actually cheating with a couple. Duh. The person kept saying her spouse was cheating with "them" -- two people, thus "they." But I was afraid of offending, so didn't ask many questions, and thought, "OK, right, the spouse is involved with someone non-binary."

People don't want to admit this is confusing, and claim you're a bigot if you try to say there's gotta be a better way than to use a plural pronoun for one person.