Randy Travis -- My Ex-Wife Sabotaged My Career!

Country legend Randy Travis says his ex-wife is a scam-artist who came up with a diabolical plot to ruin his career and cheat him out of his hard-earned cash ... this according to new legal docs.

The singer has filed a lawsuit against Elizabeth Travis -- his ex-wife and manager of 30 years -- claiming she breached her contract by running around town blabbing personal details about him in order to torpedo his career. Randy wasn't specific about the "personal details," but it sounds pretty bad.

And that's just the beginning ...Travis claims Elizabeth tried to con even more money out of him with inflated travel reimbursement requests.

The new suit comes on the heels of Elizabeth filing her own lawsuit ... claiming it was Randy who breached their contract when he canned her in 2011. She wants her full management fee.

Randy is asking the judge to block his ex from getting a cut from his future gigs.