Miranda Lambert I Didn't Cheat On Blake He Cheated on Me!

7/22/2015 1:00 AM PDT BY TMZ STAFF

0721-shelton-lambert-tmz-01Miranda Lambert has kept her boots where they’ve always been … under her bed, and says she was never unfaithful during her 4 year marriage to Blake Shelton ... but he was.

It’s a classic case of he said/she said … but sources close to Lambert say Shelton’s the one who strayed ... with a famous country singer no less.

The sources claim Blake's camp was unscrupulous, and threw mud with the help of a powerful PR firm that attacked Miranda before the ink was dry on the divorce docs.

We're told she's incensed Blake accused her of cheating with a country singer. She says it never happened, and so does the singer.

As we reported, the divorce is so bitter, Blake ordered Miranda to clear her exotic animals off his Oklahoma ranch the very day the judge made the divorce official.