Remember this: Most people that are asking are only inquiring politely. In the same way we say "How are you today?" We don't expect a great deal of detail in response to these questions.
You can respond with "He couldn't make it tonight. How are you?"
You don't owe anyone this information, so just tell people when you are ready. At some point you might like everyone to know so that you don't have to deal with questions. When that time comes you might enlist a close friend to explain simply "Shinebright and Joe have parted ways. She prefers not to discuss it right now so I am letting you know in order to avoid any awkward conversation."
When people ask you questions you don't like AFTER the cat is out of the bag you can just politely say "Oh, that's not something I'm up for talking about right now. I'm sure you understand. Tell me how you are doing?"
Until then you just say as little as possible. My grandmother was a piece of work and people would ask me about her sometimes. We're from the South, I wouldn't have said "She's most likely a sociopath." to friends that inquired. I would smile really big and say "Oh, she's the same as ever! Thank you for asking." and that was that. Even the people that had some inkling that something was amiss wouldn't keep pushing.
If you are pressured after indicating you don't wish to discuss you can raise your eyebrows and say "I'm sure you don't mean to pry, and I really appreciate you respecting my privacy right now." Or just say nothing at all and get away fast.
You won't get nearly as many questions as you anticipate.
You can keep a list of other major and minor topics on hand to use for changing the subject: "Doesn't the bride look beautiful?"
"Aren't these canape's delicious. Did I say that right? I never know how to pronounce that." Or some other distracting nonsense.
"I am so sorry, I see Mary Ellen over there and I must speak to her about something before I forget."
"Have you found the ladies room?"
Also just remember you are not the first nor shall you be the last in these shoes.
((((Hugs))))
Hanna