trans + struggling w being my bf's "exception"

Hey all. I don't know how to articulate the problem I have, but I'm going to describe it as best I can. I'm 21 and have been out as transmasc for a couple years, and I'm bi with a strong lean towards men. I just started T last week, so I'm thinking a lot about what I want for my future. I dated my current boyfriend when we were in high school and we got back together about 7 months ago, at which point I was openly, proudly out as trans. He previously identified as straight his whole life, but is a big ally and we fell for each other again so quickly I figured maybe he wasn't straight, since he was so supportive of my identity, and we didn't really have a conversation about it for a while. I've had a feeling for a long time that I only wanted to date gay men, and had we not gotten back together I wouldn't have dated another cishet person ever again. But I figured he knew what it meant to be with me, essentially another dude. I talked to him today about how we each perceive the relationship, and he sees it as a queer one, but he doesn't know what his sexuality is and generally identifies as straight still. As far as I know he's never been attracted to another man. I love him so so so much but I have a strong feeling that once the T really kicks in things will fall apart no matter how much we love each other. I feel intensely guilty admitting I don't know if I want to wait months or even a year to find out, and to have one foot in being a man who loves men and another in this space where I'm an anomaly for my otherwise straight boyfriend (until we hit a wall). It's not a matter of him not being supportive - he sees me for who I am and never misgenders me, wants me to pursue what I need - it's a matter of wanting a relationship where I share the experience of queerness fully with my partner. I don't know how to handle the slow progression towards some breaking point and feeling dysphoric about the whole thing when we have a happy, healthy relationship right now. If any other trans people have been in a similar spot or if anyone has any advice, it would be really appreciated. Thank you for reading this whole thing, it's longer than I thought it would be.