This just in:
Not all famous people are loyal.
Some cheat. Many cheat, in fact.
And, in turn, the people with whom they cheat become famous themselves.
Below, for example, is a rundown of well-known men and women who allegedly slept with celebrities while those celebrities were in relationships...
Sara Leal was the 22-year old who told Us Weekly all about the time Ashton Kutcher had sex with her in a hot tub...while he was still wed to Demi Moore.
She sort of outed herself as Jay Z's mistress after Beyonce released an album titled "Lemonade" that clearly accuse her husband of cheating. (We said Rachel Roy, people. Not celebrity chef Rachael Ray.)
Patient zero of the Tiger Woods scandal. She later went on to serve as David Boreanaz's side-piece.
London's dalliance with Hank Baskett is still stirring up drama. We hope for her sake that she's working on scoring a reality show deal.
Cady Groves was a little-known singer songwriter...until she (allegedly) broke up the biggest marriage in country music. We don't know if Cady is any good when it comes to writing country songs, but she sure knows how to live one!
Photos of Chloe canoodling with Scott Disick led to the reality star getting dumped by Kourtney Kardashian. She still says the pics were misleading, and nothing happened between them.
When Jesse James wanted to cheat on Sandra Bullock, he went for the heavily-tattooed possible neo-Nazi named Michelle "Bombshell" McGee. Yep, she's pretty much the exact opposite of Sandy.
Lamar Odom cheated on Khloe Kardashian with Polina. Those Kardashian girls sure know how to pick 'em!
Young SWEARS he had nothing to do with the end of Blake Shelton and Miranda Lambert's marriage - but cheating partners always say that. Hey, dudes can be side-pieces, too.
Whether they're Democrats or Republicans, politicians can all agree on one thing: They love getting some on the side! Rielle made headlines when she cheated with former North Carolina senator and presidential hopeful John Edwards.
Maria Belen Chapur
You may not remember her name, but Maria made headlines back in 2009, when she was identified as the reason that South Carolina Governor Mark Sanford disappeared to Argentina.
When talking famous political affairs, we would be remiss if we didn't mention Mildred Baena - the housekeeper with whom then-governor Arnold Schwarzenegger fathered a love child ... as you can see here.
Scheana - one of the stars of Bravo's Vanderpump Rules - slept with Eddie Cibrian while he was still married to Brandi Glanville. Of course, that brings us to...
The homewrecker turned home-maker! LeAnn is proof that sometimes guys actually put a ring on their side-pieces. Of course, we imagine she sometimes has trouble trusting Eddie. After all, look at how she met him!
You didn't think we'd leave out Monica, did you?! The Queen of Celebrity Side-Pieces recently re-enetered public life, and we suspect you'll be hearing her name quite a bit in 2016.
Guzman is the mother of Chris Brown's cute daughter, Royalty. Do the math, though, and it's clear she slept with Brown while he was still dating Karrueche Tran.
Tara Wallace is the mother of one of Peter Gunz's kids. But Gunz is married to Amina Buddafly, who is well aware that Peter also sometimes sleeps with Tara. It's just a mess, people.
Tony Parker didn't just cheat on Eva Longoria... he did so with his former teammate's wife!
This was crazy. The director himself was married when a photographer snapped pictures of him making out with Kristen Stewart... while she was dating Robert Pattinson!