Personally, I think I would feel the same way if my husband took to dressing up in his spare time as a Klingon, or as Batman, or as a steampunk creature with a wig & top hat, or a RenFaire knight, or a Civil War reenactor -- complete with adopted mannerisms and appropriate language for the role.
The first month he did it, it might be fun to figure it out with him. Then afterwards, it would be okay if he wore some of the gear and we watched TV together. But I think my tolerance for hanging out with him in full Civil War gear and a fake southern accent would be pretty limited.
It's NOT that I define myself in relation to him and so him changing makes me question my own identity. That's really not it.
It's just that I like one persona, the one I met, dated & married. And when he becomes someone else, no matter how much joy he finds in the role, that's hard for me because I don't know that new persona, and generally, I am not likely to like that new person. Most new people I meet are not people I want to date & cuddle with and have as roommates. So why would the new persona of my husband (whatever the persona's gender) be someone I want to date & cuddle with and have as a roommate?
