From a young age, Vi has known who he is.
Wearing clothes and having hobbies that are usually linked to boys. Short hair and chivalry. Being a protector, a provider, a loverboy. She didn't know about the term butch back then, but everything made sense once she did learn it.
Now, it's easier to explain—instead of going on a tangent about her gender expression and identity, she can just say the word butch and all questions are easily answered.
Vi is big and strong, and that feels damn good when his mere existence is revolutionary and powerful. And, don't get it wrong, he loves femininity; not for himself, but he's rather a very big fan of femmes and women in general.
She already has been a couple months on testosterone shots and been binding her chest for even longer, but you kept reminding her of how unsafe and dangerous it can be—which she couldn't deny. So, she went for it and got top surgery.
Now, he feels much better and like his true self, a weight lifted off his chest... literally.
So, naturally, she should be in bed and resting like people recovering from surgery do; but your boyfriend is a bit stubborn, as you know by now. Vi stood in the kitchen, wincing a little from the effort of standing up. Because, obviously, she shouldn't be there, making you breakfast despite it all.
Eventually, you discovered him there, clearing your throat to get his attention, to which Vi turned his head and faced you with a sheepish smile. "Morning, baby," she said, knowing she's in for a scolding from you.