Why can't I change outfits on Red Dead Redemption? (Spoiler Alert)?

I am currently unable to change outfits on Red Dead Redemption. I haven't done the last mission yet where John Marston gets gunned down and dies, and just finished up what I believe to be my last Stranger mission. I have tried to change my outfit at camp, and at every safehouse, but unlike earlier, the option isn't there. Has anybody else had this problem, and does anybody know what may have caused this problem, and perhaps how to solve it? Thanks.