I have been through therapy. Although the purpose was not to diagnose why I was the way I was, the subject did come up.
One thing to be cautious about is trying to infer some casual relationship between cross dressing and childhood recollection(s). First of all, all memories are reconstructions, and each memory evolves with each recollection. Secondly, any individual may see a connection between some recalled life experience and cross dressing. Even if there were some causal link, this might only apply to that individual case. For example, I grew up in a household that was mostly made up of males.
human beings are inherently wired to see patterns. The value is that our ancestors might have perceive patterns that helped remember signs of prey or places of ambush, which foods were in season, which berries were not poisonous. But we also have the built in capacity to imagine spurious patterns, to see relationships and to believe deeply in the validity such spurious connections.
I guess what I am cautioning against is what used to be called “arm chair empiricism”. Basically generating theory out of one’s speculations. Such theorizing may be interesting, but it is lacking in substance.
A competent therapist will not attempt to discern “why” from your life experiences, but as Sherry said, they will seek to help you cope with any problems that your attitude or your partner’s attitude towards cross dressing might be contributing to (if any).