Hi Kew,
An interesting question, and not easy to answer, as actually being in that situation is probably a lot different than sitting here pecking away at the keys while trying to imagine what it would be like.
What follows is strictly my opinion/s.
That said, if that was the only thing "wrong" with a spouse that I loved, I'd like to think I'd do my best to accept her and help her with her infantilism. If she needed to do that in public, I would probably do my best to dissuade her. If someone outside the relationship found out and had a problem with it, I'd back her up 100%. I don't have to understand her reasons for doing it, but if I love her, I'll help her do it to the best of my abilities and still love her.
However, this feels to me as if you're equating a theoretical infantile wife with "normal" wives trying to accept, or at least tolerate, a CD'ing husband. That is not quite the same thing, IMO, especially if the TG husband is dressing due to a feminine gender identity, but I can see why some wives who don't really understand TG issues might think it's essentially the same thing. Fetishistic CD'ing might be a bit closer to infantilism in they are both paraphilias. Of course, accepting it may not be any easier though.
Regardless, they are both basically harmless behaviors, as long as balance is maintained and the needs of both partners are taken care of.
OK, up on my soap box now, off on a sort of related tangent.
In my opinion, anyone who has gender identity issues should explore those issues, be honest with themselves and figure out who they are as early in life as they possibly can, before getting into a serious relationship with anyone. And a full honest disclosure early on in any relationship is a must too. It's the only fair thing for both parties.
I think I sort of gave an answer to your question somewhere in there. Thanks for the mental exercise!
Carol