The 30-year-old has been dating talent manager Brandon Blackstock since last year, reported People magazine.
"It is killing me. I'm trying to write a tough song and it is coming out like butterflies and rainbows. It is ruining my creativity. I'm writing all this happy stuff," she said.
Clarkson said her next single will be 'Darkside' but her happy love life is making it difficult to tap in to her own darkness.
"People are going to be, like, 'What the hell happened to you,'. It has been really difficult. I love it. It's an awesome problem to have."
