Holly, I'm suprised you would ask this. Crossdressing is usually about far more than "clothing choices". For many, it's about identity, not necessarly identifying "as" a female, but often "with" females......How have we allowed clothing choices to become so powerful?.....
And because much of crossdressing is connected to eroticism and very often in an unbalanced way. Just check the internet. Most all of us have dressed because of the turn-on factor. (Just watch how many will say "Not me!!!) Now, large ocean going vessels usually have more than one engine that drives them and in our case, our drives can be multiple engines, ie identity and just liking certain colors, looks and feels, as well as erotic. So when our SO's find out that we like being in the female role in dress, identity and/or sex, it shatters life long ideas of how to relate. It doesn't fit the ingrain natural pattern. That doesn't mean that it's bad or something is wrong with us, but we struggle with that ourselves, how much more they may struggle. This struggle is what tears up relationships more than the crossdressing itself.
When we go out in public, the public can see it as being a form of exhibitionism and who knows if it is or not, except for the person him/herself. It's the perseption others see.
I think the only way to change the perspective others can see, is to open up when possible and let them see inside our hearts, that we are good people - complex genderwise - but genuine good people. And that would mean showing respect to others and letting them see we may be different, but we nontheless have a good and healthy balance in our lives.