There wasn't a great fit for me among the choices, so I just picked "friends and family" as it's close enough. I'm "out" to most of my friends, unless there are circumstances where it might be inappropriate to tell them. For example, friends from certain jobs I've had in the past didn't know, but it wasn't appropriate for them to know tons about my personal life in the first place. My siblings and my mother know, but I'm not regularly in touch with most of my extended family to the point where they would need to know. They'd be supportive, but probably not terribly understanding. In their case, I simply don't see it as a necessary detail to disclose.
Essentially, if you're close enough to me that you are getting lots of info about my primary relationship, you'll be hearing stuff from time to time about secondary partners. Otherwise, I generally assume (with reason) that most people don't care and that many wouldn't really "get" it. That's fine; there's probably stuff about their life I don't care about and wouldn't "get" either. Full disclosure of every detail of my life isn't needed in every acquaintanceship, friendship, etc. However, being open is a big part of my life. If I consider you an important person in my life, I will probably want to share that piece of me to some extent with you. The level of detail obviously depends on your level of interest.