Wow, what a cool person you are, accepting your husband unconditionally! Maybe he was struggling with what he thought were going to be unacceptable thoughts and wanted to separate because in his mind, there was no one that could accept and love him the way he really is.
We all have "taboo" thoughts that we wish we could live out, but seem too out there to be accepted by our loved ones, very few people share there true self with others. It says a lot about you that you understand and accept his human uniqueness. Maybe there is a secret thought or desire you can include him in... Cross dressing, while foreign to me, everyone wants to feel sexy and desired!