A "friend" of mine decided to out me to my entire office and made up a bunch of ugly lies to boot. Seems he's the emotional equivalent of a 3-year old (although that may be a bit too insulting to 3-year olds). It was upsetting at first only because I didn't realize why everyone else was acting strangely toward me (he was such a greasy chicken-shit that he continued to pretend to be my friend to my face) but once the whole thing blew up and everyone who mattered realized what a douche he is, I got over it. Now it's a relief not to feel like I'm hiding the fact that I'm bi! With the added bonus of not having to deal with a high-maintenance friendship with someone I had lost all respect for long before it blew up. He actually did me quite a favor on at least a couple levels.
My advice is to ignore the bastard. He's probably just doing it to get a rise out of you anyway. People like this are miserable losers with zero self-esteem and do what they can to try and drag everyone down with them. They aren't worth the time it's taking to even take them into consideration.
I got outed at work, too. It wasn't by a "friend", it was by a sleazy, spineless co-worker who always acted like he was such a great "friend", even though I never trusted him. I'm not one to flaunt my sexuality, as you'd never know I am gay if you met me in person. However, this a**hole found out about me, and decided it was his job to inform everyone in my department about me. Luckily, I live in Seattle, and the "office crew" is at the corporate headquarters in the midwest, so I didn't have to deal with the awkwardness. Unfortunately, when other techs visited my area, they were heavily harrassed by other supervisors and co-workers in my department, ESPECIALLY if they had dinner with me while up here. I wondered why techs were no longer calling me when in town. It took one good friend that I'd worked with for many years to tell me what was going on, and the things that were said behind my back. It really hurt me to have the respect of people that I'd worked with for MANY years, suddenly make me the butt of their jokes, and to completely lose whatever respect I thought I'd gained from them. I never brought my personal life into work, but it took the audacity of this spineless prick to force me into a very awkward situation that I should have never had to deal with in the first place. The funny thing is, not one word was EVER said to me directly, by any of this jerks. This situation, unfortunately, led me up to the point of resigning. My resignation shook the foundation of my department, and my manager was made VERY aware of the reasons I opted to leave. I still keep in touch with some people that I worked with, and even though this happened months ago, it's still talked about.
The one thing my manager did encourage me to do was to confront the jackass that outed me. I told him I would wait until I'd been separated from the company for at least 6 months, then I would confront him face to face the next time I'm in town. I intend to do just that, but I'm also going to throw in a little bit of public humiliation of him amongst his co-workers, so everyone around there knows what kind of a piece of trash he really is. He won't have much respect left amongst his peers when they find out he was entirely behind my reason to leave. Perhaps this is a bit retaliatory, and somewhat juvenile, but I've never had this sort of embarrassment and humiliation take place through no fault of my own. Quite frankly, I'm tired of being the "bigger man" and letting things go.
The one thing I CAN say is that I did have the respect of many folks outside of my department, and now that they all know about my sexual orientation, I've had nothing but support from 99% of them.