Accidental Unicorn

I accidentally became a unicorn. I was brought in under the guise that it'd be mostly him with her sometimes, but it appears to have turned into an always them situation. don't get me wrong, she's fantastic and if anything I prefer her vibes, but when I think long term I'm struggling heavily with this. Especially because this was absolutely not what I agreed to. but now I feel like I'd need to have a conversation with him to figure out where I'm at, but I can't have one without her without feeling like I'm stepping on toes. any help?

ETA : I left. it was weighing on me too much lol.