After the river my opponent showed his hand. Thinking I had a worse hand, I threw my cards face down beyond the line but far away from any other cards. When the dealer was about to take them and muck them I realized I had a winning hand and tried to show my cards but the dealer said I mucked.
Was my hand still live since my cards were not mixed with any other cards and it was clear which my cards were?
If it's a tournament following the official TDA rules then the following applies:
14: Live Cards at Showdown
Discarding non-tabled cards face down does not automatically kill them; players may change their minds and table cards that remain 100% identifiable and retrievable. Cards are killed by the dealer when pushed into the muck or otherwise rendered irretrievable and unidentifiable.
See: TDA rules.
If it's not a tournament or the official TDA rules do not apply then individual house rules apply. Ask to see the house rules.
It's very common that a mucked hand is declared dead in those scenarios. It was the trend in the past and remains so in many house rules. I believe this got only recently changed in the TDA rules to be more recreational friendly.
This one comes up often. It's a slightly gray area. There are two issues:
Retrievable cards Generally, cars that are "retrievable" can be live. Despite what people say, "touching the much" literally means nothing in a casino. If you didn't say "fold" and you're still holding your cards, they are usually live.
Induced Action However! If your balk caused another player to act, you might very well have a dead hand. Many houses have a "forward action" rule. If your forward action [either putting chips forward or your cards] - in turn - caused another player to act - in turn - your forward action is binding.
So if you're facing a bet, and you push chips forward, it's either a call or a raise if someone acts behind you in turn. If, facing a bet, you push your cards forward, causing the player behind you to act, your hand is dead. In a heads up situation, your cards should be live.
HOWEVER.... This is a really tricky rule.
If this happened to me [well it HAS happened to me], here is what you do: Just squat. Refuse to give up your cards, seat, or money. Call the floor, call the shift, and finally call security. You have a solid chance of winning this argument. If it was a cash game, and they are taking the pot, I'd tell them I'm taking my live hole cards home with me.
