Longing

I think it would be a mistake to say that cross gender arousal in transfeminine people is synonymous with what women experience with their own bodies. One simple answer to that claim would be that women don't grow up longing to be women. However the reality of arousal does not mean one does not possess a transgender identity.

Transsexuals in particular understand very early on that there is a disconnect present within them and the desire for that to change can at times manifest itself in sexual fantasy upon entering puberty. That everything calms down and stabilizes post transition merely confirms that their search for identity had been authentic.

Conversely, a person who is content with the arousal as a payoff would have a terrible time with a transition which will only dampen male libido. 

When we are trying to understand who we are, it is this aspect which can cause much confusion since we may be unsure of motive. Once some comprehend that they can be happy with sporadic cross gender expression which may or may not lead to orgasm, they can stop asking questions and just live. However, if there is something still lingering, we will tend to want to progress forward until we have our firm answer.

The critical mistake of someone like a Ray Blanchard was ascribing the desire to transition of his patients to the arousal itself rather than to a longing which had been present from earliest memory.