Blake Shelton thinks his marriage to Miranda Lambert was ''a mistake.''

The 39-year-old country music star was previously thought to be on amicable terms with his ex-wife following their sudden split in July after four years of marriage, but reportedly wants to erase her from his memory.

A source close to 'The Voice' USA mentor said: ''Blake doesn't want anything to do with Miranda. He's telling his close friends the marriage was a mistake, and, at this point, he wants to forget it ever happened.''

The former couple, who were both the subject of cheating rumours, plan to keep things ''civil'' if they happen to cross paths.

The insider told US' OK! magazine: ''[They] remain civil if they see one another at entertainment industry events, but other than that, they'll never be friends again.

''Even though there were rumours that he was unfaithful too, Blake adored Miranda and wanted to have a family with her. Now, after all the stories he's heard, he feels like he didn't even really know her.''

Meanwhile, Miranda, 31, has been dressing sexier and partying more with their mutual friends ''to make Blake jealous.''