Tiger Woods' 1 mistress is getting divorced after her husband, Matt Hahn, filed the paperwork earlier today. Matt's reason? "Cruel and inhumane treatment."

Seriously. He put that.

The troubled couple frequently engaged in explosive, verbal arguments; Matt alleges that Rachel Uchitel slapped him after he repeatedly called her names.

There's more. Rachel called 911 on Matt on May 16 after a particularly nasty verbal argument, asking officials for help getting him out of the house.

She did not follow up with police or press charges after the situation was resolved; they didn't officially separate until today, over three weeks later.

Uchitel has not responded to the divorce filing.

Rachel and Matt Hahn, a former Penn State football player, were married a year-and-a-half ago. They got together after her flings with Tiger and David Boreanaz.

Uchitel welcomed their first child, a daughter, last year.

UPDATE: Hahn is asking for custody of their daughter as well as child support and spousal support, plus an "equitable distribution of marital assets."

It's unclear if there's a prenup, but it's fairly certain that her settlement from Tiger - he paid her a LOT to shut her yap back in late 2009 - will remain hers.

Hahn states in his divorce filing that her conduct was such "the defendant [Rachel] so endangers the physical or mental well being of the plaintiff."

Put another way, he's scared out of his mind of Uchitel, whose behavior "renders it unsafe or improper for the plaintiff to cohabit with the defendant."

Tiger always did like it "rough."