Louis Russell was on "Too Hot to Handle," not "The Ultimatum" ... but he says his ex gave him one concerning their kid -- break up with Huda, or you can't see your son! In court documents, obtained by TMZ, Louis claims his ex-girlfriend, Nicole…

Big drama for Huda Mustafa ... her boyfriend Louis Russell's ex-girlfriend is seeking court-ordered protection from the "Love Island" star, alleging Huda threatened to kill herself and tried to break into her home. Nicole Olivera beelined it to…