I need help because my brain can't make up its mind

[granite ravine]

I feel like I'm in a very specific situation. I came out to my friends as bisexual in June, but things have changed very rapidly. First of all, I've realized I'm not actually bisexual. I thought I liked women, but discovered that I just... wanted to be one kinda? I don't know how to describe it, especially since I know I'm not trans. I guess the two identities I think most accurately describe me are genderfluid or femboy? I suppose I feel comfortable enough as long as I'm not definitively a man or woman. But neither of the identities I've found fully fit.
Now here's another big issue: I started dating a guy. He's amazing and wonderful and makes me feel incredibly comfortable, so I think he deserves to know about my gender struggles. I do think he would fully support me, which I really need right now, but I just don't know how to bring it up or what to say.

So, I essentially have to come out AGAIN, just this time instead of being about sexuality, it's gender, and instead of being inaccurate and discovering not long after, I just won't know anything about what is accurate.
If you have advice, I need it.

[plain barn]

It will probably not be the best advice or anything since I‘m not trans, genderfluid or anything like that but I my ‘advice‘ (if you can call it that) would be that you could ask him something like ‘if I would be genderfluid/a femboy what would you say?’ But like in a joke way so you can still say it’s a joke when he says he wouldn’t be supportive or anything. You can of course just tell him, that’s a better solution anyways but you have to be ready for that.