Read This & Judge Them Yourselves. WRONG SEX

A man comes back from work at
night & heads straight to the
bedroom to make love to his wife. He
got into d blanket & they made a
quick one. When he's done, he goes
to d kitchen only to find his wife
looking for something in the fridge.
He asked her how she quickly made
it to the kitchen when they've just
made love.
Alarmed, his wife shouted, "that was
my mother in d bedroom, she was
tired when she arrived so i let her
sleep in our room."... Wife runs to
her mother & asks, why she didn't
say something when her husband
started. Mother replies and says:
"Hey! you know me & your husband
don't speak to each other and i
wasn't going to start today. I'm too
old for that"
QUESTION
Who is at fault among these 3
people?
1. Husband
2. Wife
3. Big Mama