Okay, so you've been full-time, maybe even post-op for a while now. You pass pretty-much perfectly, your old life as a member of the opposite sex is little more than a bad memory...
Then Cupid comes along, uses your butt for target practice, and you are smitten. Problem is, they're straight, just that bit less open-minded than they think they are...
You get the scenario.
So when do you tell, if at all? If pre-op, do you just claim abstinance until you can sneak away to have some surgery, or if post-op, simply hope it never comes out? Do you tell, and if so when. Give it enough time, and they might just realise that their prejudice is damn-silly, but wait too long and its a betrayal, or tell too soon, and they just run-off...
Or do you decide to take up celibacy and start meditating three times a day?