Nicole Scherzinger and Lewis Hamilton Break Up in Wake of Engagement Reports

Former Pussycat Doll and boyfriend of five years reportedly too busy with work schedules to make a go of it

Nicole Scherzinger and Lewis Hamilton's relationship sure is tricky to keep tabs on!

Just weeks ago, Lewis reportedly said he wanted to propose to the former Pussycat Doll by 2014. But on Monday, a source confirmed to E! News that she and her boyfriend of five years had broken up.

The reason for the split? A source told the British tab that Lewis, a Formula 1 racing driver, and Nicole, an X Factor judge, were simply too caught up in their jobs. "Both have supported each other in their careers and will continue to do so. But the nature of their work ultimately cost their relationships," a source told The Sun.

NEWS: Nicole wishes she were more "slutty"

When Lewis, 28, was recently asked by The Sun if and when he would be proposing to Nicole, 34, he answered "…hopefully in the near future." He also noted that having been together for five years "is quite a milestone really," and he might pop the big question "before we get to six years."

Talk about a possible walk down the aisle is nothing new for these two though. In 2011, Glamour U.K. asked the duo whether they would be getting married anytime soon. "We're just really happy at the moment," Lewis answered. "She's focusing very much on her career."

He did admit, however, that they hadn't seen each other in three weeks. "But we just make it work," he said. "It's a long distance relationship. It works out."

When asked the secrets to making a long-distance relationship work, Lewis replied, "Trust, honesty and communication."

Nicole agreed, adding in, "Have fun when you are together! Laugh a lot!"

They certainly seemed to do just that, but Lewis also provided support for Nicole on a serious issue. In an episode of VH1's Behind the Music that aired in 2012, Nicole said that it was her then beau who "gave [her] the courage" to overcome her battle with bulimia.

"He made me feel beautiful for who I am and not what pant size I'm wearing, and that helped a lot," she said.

Aw. Well, even if Nicole and Lewis don't reconcile their romance (as they have done before), something very positive came from their time together.