Sob their hearts out - Idioms by The Free Dictionary
sob (one's) heart out (redirected from sob their hearts out)
sob (one's) heart out
To cry for an extended period of time. Poor Jane really sobbed her heart out during the funeral service. I can't watch those sappy movies because I just sob my heart out every time.
sob your ˈheart out cry noisily for a long time because you are very sad: After the argument she spent an hour sobbing her heart out in the bedroom. OPPOSITE: laugh your head off