According to reports, Mollie, 28, wants to start a family but 35-year-old David is still putting his career first.
It’s thought The Saturdays singer Mollie finds it hard to see most of her friends starting families while she’s unable to get model David to commit.
A source told The Sun: “Mollie and David reached breaking point in December and have decided they need some space.
“They were having huge arguments about his career and how he is hardly ever around. He said he was going to quit modelling but he is still designing clothes for M&S and flying all over the world.”
The source added: “Mollie wants to start a family and is desperate for him to commit. Almost all of her bandmates have kids and it’s difficult for her to see them then go home to nothing.
“David doesn’t want kids at all right now. His main problem is that he is too much of a loner.”
Last year The Saturdays announced a hiatus, making it the perfect time for Mollie to think about children.
Her bandmates Rochelle Humes, Una Foden and Frankie Bridge have all started their own families, which is said to be one of the reasons Mollie is so determined to have a baby.
Mollie and David first started dating in April 2011, before splitting in February 2012. They got back together in August last year.