The "other man" who helped destroy a marriage on national TV — getting his ex to admit to 8 million viewers that she'd rather be married to him than her hubby — is "sick" over his role in the scandal and says he made a mistake appearing on the show.

"I really just want all of this to be over," Frank Nardi Jr. wrote in an e-mail to The Post yesterday about his stomach-churning appearance on the lie-detector reality show "Moment of Truth" Monday.

The fledgling New York actor, who goes by the online nickname "Nardiballs," also wrote on his MySpace.com page yesterday: "This whole experience was a mistake ... I haven't been this sick ever in my life.

"It wasn't my intention to go out and ruin a marriage."

But that's what happened when Nardi, 25, turned up as a surprise guest on the controversial Fox show where his one-time gal pal, Lauren Cleri, 26, made viewers squirm after admitting she'd cheated on her husband.

Click here to read the rest of this story in the New York Post