It is hard to keep up with the revolving door of their relationship, but - if memory serves - they've split about three times previously and mostly it's been Lewis doing the dumping.
This time around, the former Pussycat Doll is said to be 'very upset' after ending her seven year relationship with the F1 star following a series of squabbles over the festive period.
While the couple were believed to be planning to wed last year (news to me), it is thought the brunette had grown tired of waiting for her 30-year-old beau to put a ring on her finger, with a source informing The Sun: "It really is over this time."
It is said the pair had been spending less and less time together after Lewis - who bagged his second F1 championship last year - revealed plans to go for a third and Nicole joined the West End production of Cats.
A source elaborated somewhat with: "They'd been fighting for months but things had got much worse. They spend so much time apart that things just became untenable.'
Lewis also confessed that he was feeling pressure from the 36-year-old singer's family to pop the question but insisted the pair were too busy to tie the knot when he was questioned over their relationship back in December.
He said: "I'm certainly feeling pressure, heat from family members. But Nicole's massively focused on her work the same as I am. We're happy just way we are. [Marriage at] one point... will be for us." And, according to Lewis back in 2013, that point was last year - "before we get to six years."
He added that the couple were too 'young' to start having kids: "She's amazing with kids, I think we're both pretty good with kids... but we don't have time for that at the moment. There are so many things we want to do, but the great thing is that we support each other with it. All in good time. She's still massively young and I'm still young man!"
Listen, let's be frank, if 36 is her showbiz age she's probably a fair whack older than that - which will be on her mind if she wants kids. Not that that's any of our business.