Has your therapist read this new textbook (2013) for LGBT therapists?
http://www.amazon.com/Counseling-LGB.../dp/1412987180
Here's the full chapter on crossdressers. It includes citations to major studies done in the area. You will see there are different theories.
http://www.sagepub.com/upm-data/47510_ch_7.pdf
By definition, crossdressers are male identified or gender-nonconforming (gender-fluid if you will). Else they would not be crossdressers, they would be female-identified transsexuals.
This is not true, if you look at the vast population of male-identified CD fetishists or CD non-fetishists, who do CD in private and who are not in the least bit interested in identifying as a woman. Read some of the threads in this very forum about this, and also do a google search of CD + sex and have a look at the millions of websites that cater to the fetishists, far more than there are support websites for the CDers.
They do not transition precisely because they do not hate their male sexual characteristics. They would not be happy living as women full time nor would they be happy without their male sexual functioning. I think it's a mistake to paint all CDers as men who float in the breeze according to societal mores and who don't transition because they fear losing their families and risk being stigmatized. The simplest explanation is that they are exactly where they want to be, even though the fantasy of living life as a woman is tantalizing.
I suppose there are arguments for both sides of this debate. But please read the link above together with all the threads we've had here by members who do not identify as women. There is a difference between transsexualism and gender-nonconformity (and just plain old crossdressing) and it's more than having various degrees of gender dysphoria.
BTW - transitioned TSs will tell you it was not technically gender dysphoria they had (they actually were quite clear what gender they are), it was more a question of being dysphoric with their bodies (their sex).
I believe there are however, (although this is difficult to measure), gender-nonconformists who either do not know if they are, or would rather think themselves as transsexual. I think it takes time for many people to navigate through this most difficult determination and in the end, there are those who will discover they are TS, while others will discover they are not.
And last, there are therapists (not all of them) who do have tunnel vision possibly because of their limited exposure and/or their own personal bias. Some of these therapists believe that everyone who dresses must have GD, while others believe that everyone must be inherently fetishistic. The truth is, there are TSs, there are fetishists, and there is everyone in between including those who have partial GD and those who have not.
I think it would be helpful to seek a therapist who has successfully counseled a healthy mix of both TSs and CDs.