Any crossdresser would have a problem or 99% of them, anyway. It wasn't that she reacted, it' was HOW she reacted. I don't believe it was attraction that that would be the opposite of what the SO was spouting. Stephanie was looking for acceptance , or at least tolerance.
IF Stephanie decides to tell, than yes, that would be the ideal way to go.
First question would be no, no one knows absolutely everything. Quest. 2, that would have to be on a case by case basis. Support for doing something immoral or evil would probably not be forthcoming, for example. Questions 3 & 4, yes I believe that many cders would forgive ( we know how it is, remember?) if there was a very good reason not to share it (fear, societal pressure, hate, loss of family, friends, jobs).
Again, we as cders know all that too well.
Sorry, but I think that is just being mean-spirited. I also think that very few couples are 100% emotionally intimate with each other, especially couples that have a known transgender issue. My opinion is that cders would love to share all that with the wife or SO. But because of the reasons already laid out earlier, many feel they can't. They know they are missing out on that sharing, and it hurts.