Male Escort Clayton Howard Claims Cassie Gave Him STD, Aborted Their Pregnancy

Clayton Howard, one of the male escorts prosecutors say Diddy hired, is dragging Diddy and Cassie to court ... and he says Cassie gave him a sexually transmitted disease and got an abortion after he got her pregnant.

Howard, who says he went by "Dave" when he was hired for freak-offs with Diddy and Cassie, makes the salacious claims in a new lawsuit obtained by TMZ.

The escort claims he contracted an STD from having sex with Cassie ... and he says he impregnated her and she aborted the pregnancy without telling him  ... and he alleges she then continued having unprotected sex with him.

Howard is one of 7 male escorts federal prosecutors in Diddy's criminal case say were transported across state lines for the purpose of prostitution.

He claims he was hired for freak-offs with Diddy and Cassie starting in 2009 and he says for more than 5 years, they trafficked him for the purposes of commercial sex, using him as "entertainment to satisfy their sexual fetishes and personal ambitions."

Howard claims Diddy and Cassie drugged, manipulated, and traumatized him while they themselves engaged in a toxic, domestically abusive relationship that often became violent.

He says Cassie manipulated him into taking ecstasy and having unprotected sex ... and he says she would order him to masturbate for hours on end, resulting in tears, skin peeling and scabbing to his penis.

Howard claims his dealings with Diddy and Cassie left him with physical and psychological injury, lost wages and benefits, medical expenses, pain and suffering, emotional distress and mental anguish, plus loss of enjoyment of life.

He was not called as a witness but was mentioned several times during testimony in Diddy's trial. A federal agent testified about Clayton’s stay at a Four Seasons and a flight from NYC to LA, all paid by Diddy.

Diddy was acquitted on racketeering and sex trafficking ... but was found guilty of transporting escorts across state lines for the purpose of prostitution. He was denied bail and remains in custody awaiting sentencing and is facing up to 20 years behind bars.