I don't have statistics to back me up, but based on conversation with other crossdressers in the community, revealing to your girlfriend or wife that you crossdress is akin to playing Russian Roulette with your relationship (except there are probably 5 bullet rounds in the chamber rather than 1). There's a chance that you'll come out unscathed, but the odds aren't very high. 

I've heard too many stories of regular(?) relationships that crossdressers have ending in divorce or breakups. Or if the relationship continues, there is simmering unhappiness and discontent on both sides; the guy will be feeling constrained and unable to freely dress up, needing to take various measures to do it behind the wife/girlfriend's back, causing the crossdressing behaviour to go deeper underground. While the girl will either be constantly wondering if her husband/boyfriend is crossdressing behind her back, or be worried that he might decide to transition all of a sudden to live as a woman full time, which is way more than she had bargained for.

Vivienne, a New Zealand based blogger who writes about crossdressing, documented on her blog how her marriage began its downwards death spiral three years after tying the knot, when she revealed to her wife about the crossdressing. It was quite a sobering reminder that even in a developed nation fairly accepting of LGBTQ members in the community, when things hit close to home, acceptance may not be as easy. 

I can fully understand the conundrum that wives and girlfriends have to face when their special other owns more high heels than they do and prefers wearing dresses and lacy lingerie over regular men's wear. Their entire mental model of how their partner should be is thrown out of the window in an instant. Flip it around and it's easy to appreciate how challenging it is for wives and girlfriends to accept crossdressing. Imagine one day during dinner, your wife/girlfriend tells you that she prefers to bind her breasts, wear boxer shorts to bed and shave her beautiful long hair into a crew cut because it makes her feel whole when she dresses like a man. How many husbands and boyfriends will balk at such a revelation? Of course, women wearing men's clothes in society is more easily accepted than men in dresses, but if you turn the masculinity dial up a few notches (like the scenario I described), it requires a big shift in the guy's mental model of how his spouse should look and behave. 

The "woke" community can argue to say that gender is not as binary as society has led us to believe, people should recognise this fact and be more accepting if their partners want to dress in a certain way. They are right that there should be greater acceptance. But the harsh reality is that society is very clearly split into two genders; Male and Female. We have been raised for years to identify certain traits as male and female, boy and girl (even my kid at 18 months old could easily point out whether someone was an "Uncle" or "Auntie"). It is going to take a good number of decades before gender fluidity can truly be accepted in mainstream society....if it is ever going to be at all. Even as a member of the LGBTQ community, I struggle to get my head around the bearded lady or guy in a dress aesthetic that some in the community go for (e.g. Billy Porter, Conchita Wurst); let alone someone who is less immersed in the concept of gender fluidity. 

Not all crossdressers' marriages end in tragedy of course (although I believe they still remain the minority). Apart from myself, I know crossdressers whose wives accepts their husband's crossdressing. For a lucky few, their wives even partake and enjoy the crossdressing behaviour. Usually for such cases, the secret is revealed prior to marriage, meaning that it was a conscious decision by the wife to decide to marry the guy despite knowing his feminine inclinations. 

For younger crossdressers who have yet to commit to a relationship, it is a good rule of thumb to be upfront about your crossdressing inclinations from the start (perhaps on date 3 or 5?). It is heart-wrenching to see a potential partner do a 180 degree after you do your big reveal, but think about how much more painful it is when you have committed years into a relationship and have marriage looming ahead. Or worse, you have a house and kids, but are suffocating inside because you are unable to let your female self loose once in a while (trust me, once you move in together with your wife, the "oppressiveness" and latent stress you feel from the need to constantly hide is no joke.). Although society isn't 100% ready for gender fluidity, each generation is becoming more accepting and open. So be just a bit braver while you have youth on your side.