Rihanna and Chris Brown

Rumored to be dating since late 2007, Rihanna and Chris Brown were the reigning cute young couple of music at last winter’s pre-Grammy parties. But their love turned dangerous in the early hours of February 8, when Chris, 20, battered Rihanna, 21, during an argument in his car. Though he begged her forgiveness and eventually pleaded guilty to charges, Rihanna broke it off. “He didn't accept that very well. Obviously he didn't want us to be apart. But I had to make a decision for me,” she told 20/20, adding that she still loves him. “I want him to do well, have a great career, have a great life and grow up.”

Read 10 Hottest Couples of 2009

Lindsay Lohan and Samantha Ronson

Lindsay Lohan, 23, and DJ Samantha Ronson began their romance in 2008 and over the next 18 months their public brawls and tearful reunions became legendary — Sam, 32, even threw Lindsay’s clothes out the window of her home into the street during one lover’s tiff. Friends say the volatile duo finally parted ways for good in October. “I'm in love with her, as she is in love with me,” Lindsay Twittered in the aftermath, “but her loved ones hate her brilliance & resent her happiness."

Jessica Simpson and Tony Romo

Jessica Simpson once called Tony Romo “the love of her life,” and it looked like they were headed to the altar, until the Dallas Cowboys quarterback abruptly dumped her the night before her 29th birthday in July. Tony, 29, who began dating Jessica in 2007, reportedly wasn’t ready for marriage. Though friends say Jessica was stunned and heartbroken, she struggled to remain optimistic: “Everyone needs to know that hope floats,” she Twittered post-split. “Grab the strings and pull it back to you."