The singer of The Smile, who faced Piers Morgan, host of Good Morning Britain, spoke frankly about their dark days at the Boardmasters festival in Newquay.
Lily and Sam were married for five years from 2011-2016.
During her performance, the pop star said: "I have not been present for four years because I've been divorced and I'm developing an unhealthy relationship with alcohol."
After laughing, the eccentric actress added: "My song Family Man is about my divorce.
"Actually, it's about how I felt before the divorce … I thought it was going to work."
Referring to her song My One of 2018 in which the 33-year-old singer sings about "sleeping with half the children in Paris" and having a night in Texas, Lily added: "Basically it's about me flying around the world. yf * ** people ing ".
"Basically it's about me flying around the world and fucking people"
Earlier this year, Lily released her fourth album No Shame.
Throughout the record, which has seen the mother of two being nominated for a Mercury Prize Award, Lily sings about the failure of her marriage, becoming a single mother and substance abuse.
Before talking to Daily Star Online about the album, Lily said: "There was not a big investment behind this album, it is what it is, it feels natural and organic.
"He's so frank that he is what he is."
"You do not need to use your imagination, it's just there.
"Really, I really fought in the last few years and tried to be as honest as I could."