Just to tag onto what Virginia says (hi!), yes, there's a different kind of intimacy in a relationship that isn't predicated on disclosure. "Coming out" when you're already where you want to be is kind of asking someone to start treating you differently than they already are. If you're being gendered correctly, well, isn't that what this is all about?
Of course, it's possible that the information will come around from other quarters. So let me tell the story of my friend "Raquel Welch," for that's pretty much how she came across. Raquel was dating this fella Jack, and kept a closed narrative. About six months down the line, they're in love. Then, he finds some information related to property records (he was in real estate, and naturally curious) and so he asked her what was up.
Now, this is a very different situation than volunteering a narrative. Raquel didn't ask for this, Jack did. So she tells the story, and explains that as far as she's concerned, she's past all that, she's female now, and that's the end of the story. If Jack wants to continue the relationship with her, he'll have to accept that narrative, or it's not gonna fly. Oh, and after one week, the subject is never to be brought up again.
He married her a couple years later, and they lived happily ever after.
Happily, because she knew exactly what she wanted, and lived her life that way.