Joseline Hernandez was NOT on drugs during that ugly brawl on the set of "Love & Hip Hop: Atlanta"... so says her husband Stevie J -- who tells TMZ they're gonna sue the liars who said she was high.
Stevie claims his co-star, Althea Eaton, made up the story about Joseline smoking crack cocaine before attacking her last month at the reunion show. Althea is suing Joseline for assaulting her.
Stevie tells TMZ ... the suit is BS because Althea and her fiance Benzino started the fight by talking crap in the first place. He claims Althea's lawsuit is a smokescreen ... to hide the fact Benzino slugged Joseline during the tussle.
Stevie says he and Joseline have lawyered up ... and plan to countersue because "no grown man should hit a woman."
We called Benzino who told us, "It's clear that him and his whore jumped off the couch and attacked us and whatever happened from there was merely self-defense."