Hollywood star Sienna Miller has reportedly called off her worldwide media romance with married oil heir and actor Balthazar Getty after a series of alleged fights over their different lifestyles.The actress is alleged to have recently flown back to her native Britain after initiating a "cooling-off" period with Getty.She is claimed to have clashed with Getty, who recently announced his separation from wife Rosetta, over his reluctance to file for divorce. The former couple has four children together, ranging from eight years to 13 months old.However, according to Britain’s Mail on Sunday, reformed alcoholic Getty is also fed up of Miller’s partying lifestyle.So the couple has decided to spend some time apart in a hope to save their relationship, the newspaper claims. A source tells the publication, "Sienna is back in London to give them both some cooling-off time. They are still together at the moment but she has said things aren’t good. There have been some pretty unpleasant rows, largely over Balthazar’s reluctance to commit."She has really wanted to be able to step out as a couple but Balthazar is very torn over his children and it looks like he might be wanting to go back to his family. Sienna is devastated… Sienna is totally paranoid he is going to go back to his family. She feels very let down by Balthazar."