R W. I play guitar too. I would rather spend ten hours pounding out riffs than ten minutes on a treadmill. I am kind of lazy though. I sweat and exert the same amount of energy per hour but one I enjoy and the other (tread mill ) I hate.
I really can't understand the total nightmares of dysphoria though. Yes I have experienced it but not on a level some do. I am almost 50 and tackled the trans thing when I was younger and was called a sissy, ->-bleeped-<-got or gay. So in all honesty I don't get he anxiety attacks and so on. Not that I don't understand and it may have been more of an "IDGAF" attitude. Yes I have been anxious when buying makeup, clothing, shoes and so on in the past but not really anymore. But I am not married to a woman anymore either. When I was it sucked shopping with her and not buying for myself.
Meditation is a really good way to calm you down. Conscious breathing is another. Other things too but take it slow. If she bought you a sports bra then maybe you might have it made. So just calm down and be yourself. Open up a little at a time to your wife and see how she reacts and take it from there.