fair weather friendship, n.All

Fair-weather friendship (n.) ends ⁠​‌​​​‌​​​‌​‌‌​​​​‌​‌​​‌‌​‌​​‌​​​​​‌‌​​‌​​​‌‌​‌‌​⁠where it began: whoever becomes your friend because it pays will stop because it pays.