Hamilton, 29, however, said that he and the Pussycat Dolls singer are good with kids, reported Digital Spy.
"With our careers people perhaps don't understand that she lives in LA, I live in Monaco and we're in and out all the time.
"Schedules are changing all the time. She's doing Cats now, which means she's in the UK for the next two months, and I go away and do my training, so during the year we're always apart, but people can see there's a lot of depth there - we've been together for almost seven years," Hamilton said.