One of life's greatest taboos is dating a close friend's ex. Regardless of how amicable the break up was, no one wants to meet up with their friend at party to see their former beau on their arm. It's an absolute no-no.
We confide in our friends about our relationships - they're the first to know when our partner has messed up. After a break up, it's not uncommon for your close friends to stalk your ex online on your behalf.
This is done so that they can provide you with moments of much-needed hilarity about when you're feeling down about the break up, and, let's face it, it would be seriously unhealthy for you to do the stalking yourself.
"Have you seen who your ex is dating now?!" they cackle. "They've gone from riding a Bentley to a junkyard clunker!"
So it came as no surprise that Tom Cruise wasn't amused when he discovered that his ex-wife Katie Holmes had been in a secret relationship with his former bestie Jamie Foxx, who he famously starred in Collateral (2004) with.
Tom Cruise was married to Katie Holmes for six years between 2006 and 2012, which, in the world of celebrity marriages, is a sizeable amount of time. What's more is that the two have a daughter together, Suri.