Get it off your chest

Get it off your chest:  desabafar, confessar para alguém algo que está incomodando

“I can see that something's upsetting you, so why don't you get it off your chest and tell me what it is. You'll feel better if you do.”

“Charlie was feeling bad about cheating on his wife, so he got it off his chest and told her about it. She divorced him soon after.” (www.englishclub.com)