This is definitely not an easy issue. Not least because how someone else perceives the world or thinks about a person can be very difficult to change, if at all it's possible or even ethical to ask them to change. I myself have the "discussion" every other night about no matter how much he understands biology and personal choices, he himself is caught in the uncomfortable space between understanding and respecting, and what 'feels' natural for him to perceive. I know he is going to have issues when I stop looking female and start looking, sounding and smelling male.
As for roles though, I would not advise changing what you enjoy or feel comfortable with for the sake of that. Unless it is some role that you are not comfortable with. Even in gay male relationships there are varying degrees of 'masculine' or 'feminine' behavior and sometimes one partner is much more feminine in ways than the other. It is not uncommon; the main point is that in such relationships there is still no argument about them both being men.
I've found that I can't be 100% sure if I'm being thought of as male or not, despite being bigger, physically stronger, more assertive and more aggressive in nature than my partner. A certain amount of peace of mind in my case comes from feeling that what I think on that matter is the most important, followed by the probability that T will do its work, and also that I am 100% comfortable doing most roles I do. If I am not, I will say so. Socially I do not really play much of a feminine role. I guess the most traditionally feminine role I do and the only one I do is that I do almost all the cooking, and that's because his cooking is freaking awful, mine is awesome, and I don't want to eat amorphous, overcooked gunk. Other than that we both share all the house tasks, we play videogames together, go out drinking together, watch the same kind of movies together, go visit places together, etc.
I find that I only tend to do specific roles if I am picky about the result, such as the food, or the kinds of food that gets bought. If that's feminine behavior, I don't really care, I want a quality dinner. The social role that used to come with being "the girlfriend" i.e. the person his relatives would chat to because I was just more talkative or whatever, I decided to just drop and let him handle it if they're his relatives. That just sorts itself out without me needing to be the social lubricant. A lot of those feminine expectations or responsibilities won't actually chase you down if you choose to drop them.
How to get out of the female social box? I guess realize that the door of the box has always been open, and walk out. You don't have to do/say/be things you don't want to. As a male you won't be expected to do them. But don't do things for the sake of distance that make you appear to be clutching because your boyfriend will notice if it's not "you". If there's something you genuinely always wanted to do but never felt you should because of prior female status tell him it's something you always wanted to do, and that won't be a problem.
