"The Real Housewives of Potomac" reunion special got real when Monique Samuels accused Pastor Jamal Bryant of having an inappropriate relationship ... and she's not backing down, despite his threat to sue her.
ICYMI ... Monique threw major shade at the pastor last week on part 1 of the special -- claiming she had proof he was involved with a woman in his congregation while dating Gizelle Bryant. She even put his phone number on blast.
Jamal fired back at Monique with a cease and desist letter -- obtained by TMZ -- accusing her of "maliciously spreading inaccurate and unfounded information" on TV that defames him .