Simon Cowell -- Accused of ADULTERY In Friend's Divorce

Simon Cowell is a homewrecker -- at least according to his good friend who filed divorce papers accusing Simon of banging and then knocking up his wife DURING their marriage, TMZ has learned.

Andrew Silverman has filed divorce docs in New York and TMZ has learned he's alleging ADULTERY in seeking to end his marriage to Lauren Silverman ... who is believed to be pregnant with Simon's child.

It's pretty shocking ... in New York claiming adultery is like a legal nuclear weapon ... if proven, the cheating party (and Simon) can be forced to take a DNA test -- something that's hard to get in New York when a couple is married and the wife gets pregnant.

In the docs, Silverman, the plaintiff, lists Lauren as a defendant and Cowell as a co-respondent.

Andrew doesn't pull any punches in the divorce papers, saying, "The nature of this action is: to dissolve the marriage between the parties based upon (1) the commission of acts of adultery by the defendant and (2) defendant's cruel and inhuman treatment of the plaintiff."