Leann Rimes' ex-husband says divorcing him was ''the dumbest thing she ever did.''

Dean Sheremet, who split from the singer in 2010 after seven years of marriage as a result of her affair with now-husband Eddie Cibrian, thinks her career has suffered since they went their separate ways.

The former dancer turned chef said: ''The dumbest thing she ever did for her career was divorce me... Because we were such a good team. The last hit song she had was when she was with me. It was 'Nothing Better to Do.' ''

Dean claims he was the 32-year-old beauty's ''husband, father, friend, lover [and] manager'' during their relationship, but admits he slowly started to resent her.

He told lifestyle blog Nat'sNextAdventure.com: ''This is childish and I recognise that now but I never thought I got the credit I deserved for the work I did. So that resentment slowly built over time. I have my own dreams and goals and I felt like there wasn't room for me.

''I came to the realisation that my name was never going to be on the marquee. No matter how much I put into this show or that tour, it was never going to be about me. And that was a really big moment.''

But the 34 year old was blindsided when he found out that LeAnn was cheating on him with her 'Northern Lights' co-star Eddie, who she married in 2011.

He said: ''Never in a million years did I think something like that would have happened. The need for me in her life was so strong. There were things she couldn't do without me. She had her own phone but never used it. People would call me to get to her. Everything went through me.''