I'm not on HRT yet, and transitioning the other way, but this is a huge issue with my weight loss, though getting thinner helps a lot. Also don't make the mistake I did with hitting the hip adductor machine hard...you really don't want more muscles in this area...chafing is horrible no matter what gender...
I used to be super skinny when I was younger, and walked all over the place and never had this problem.
I gained quite a bit of weight later, and this became a big problem. And of course, walking a lot less added to the weight problem...
It is a lot more of a problem if you are sweating. Take your walks at dawn/dusk/night and there will be less reasons to sweat. If you are already irritated there, you just have to take a break, unfortunately...
Also, men's clothes, especially jeans, are a lot thicker and rougher, and thus tougher on the inner thighs than women's are...