go sour
US /ɡoʊ ˈsaʊər/
UK /ɡoʊ ˈsaʊər/

1.
desandar, azedou, dar errado
to turn out badly; to become unpleasant or unsuccessful
:
•
Their business partnership started well, but then things began to go sour.
A parceria de negócios deles começou bem, mas depois as coisas começaram a desandar.
•
Their relationship began to go sour after a series of arguments.
O relacionamento deles começou a azedou depois de uma série de discussões.