EXCLUSIVE

The "Blood Sugar Sex Magik" is dead for John Frusciante and his wife -- the former Red Hot Chili Peppers guitarist is getting divorced ... TMZ has learned.

Frusciante and Nicole had a decent run of nearly 4 years, before she filed the divorce docs in L.A. ... citing irreconcilable differences.

The couple didn't have any kids -- so child support won't be an issue -- but Nicole is asking for spousal support, and attorney's fees.

John, who's retained Laura Wasser as his attorney -- will have to give it away, give it away, give it away in the name game. Nicole wants to drop Frusciante, and go back to Turley ... her maiden name.