Home Game - Argument gets started

[Djcoax]

So on a beautiful morning I decide to organise a home game with some of my closest friends. We set it up , some of us have been playing poker for some time now. There are 3 or 4 that have never played before. So we send them all the info a week before the game. We explain in detail. We play for an hour for no cash whatsoever.

One of my best friends brings along his wife. She has never played but the fact that there's money involved that she can get for free from other people , she starts liking the game.

After a couple of hours of play , me and the guys wife are the only ones left - having cleaned up the rest. She goes all-in , I call. I win everything.

Couple of days later the guy starts bugging me saying that upon review of the board and her and my hand , they are sure that it was a tie and not a win. According to me I clearly won with an ace high straight , while she had a king high straight.

He keeps on contesting and now asked me to pay her buyin for the next homegame ("because that would be only fair")

What the hell should I do .. it's a small price to pay to make this crap stop , but on the other hand I am pissed that this kind of thing even happens. Why can't she just realise she lost the game?

So my question is : is there a sort of poker etiquette that eventual hands can't be contested anymore after they have been played out ?