Adam Levine "crossed the line" with his flirtatious behaviour - but has denied cheating on his wife.
The 43-year-old pop star has rubbished claims made by Instagram model Sumner Stroh that he cheated on Behati Prinsloo - although he's confessed to showing "poor judgement".
In a statement on Instagram, Adam - who has been married to the model since 2014 - said: "A lot is being said about me right now and I want to clear the air.
"I used poor judgment in speaking with anyone other than my wife in ANY kind of flirtatious manner. I did not have an affair, nevertheless, I crossed the line during a regrettable period in my life. (sic)"
Adam and Behati - who have Dusty, five, and Gio, four, together - recently announced they're expecting their third child.
And although Adam has confessed to "inappropriate" behaviour, he's promised he won't repeat his mistake.
He said: "In certain instances it became inappropriate; I have addressed that and taken proactive steps to remedy this with my family.
"My wife and my family is all I care about in this world. To be this naive and stupid enough to risk the only thing that truly matters to me was the greatest mistake I could ever make. I will never make it again. I take full responsibility. We will get through it. And we will get through it together.”
The Maroon 5 star made the statement after Sumner claimed she dated the singer for about a year. She also shared Instagram messages that she claimed were from Adam.
Sumner said in a TikTok video: "At the time, I was young, I was naive and, quite frankly, I feel exploited."
The Instagram model even suggested that Adam wanted to name his third child with Behati after her.
Sumner explained: "He said, ‘Ok, serious question. I’m having another baby and if it’s [a] boy I really wanna name it Sumner. You OK with that? DEAD serious.’"