Kordell Stewart -- I'M NOT GAY ... Despite What My Ex-Wife Says

Kordell Stewart is adamant ... he's NOT GAY ... despite his ex-wife going on "Real Housewives of Atlanta" this week and suggesting otherwise.

The former Pittsburgh Steelers QB just appeared on V-103 ... just two days after Porsha Stewart said on her Bravo reality show she had questioned K's sexuality.

"There were definitely times in the marriage that Kordell didn't necessarily want me physically," she said.

She also explained that when she questioned if K was gay, it was based on "things that I had experienced or seen."

Now, Kordell is lashing back ... claiming he's not gay, bisexual -- "I'm 100% man."

Of course, the issue with Kordell's denial is the insinuation that gays are not 100% men.

Still, Kordell continued, "I don't do no homophobic. I don't do no none of that. There's nothing about no dude that I see."