The estranged wife of Sienna Miller's lover Balthazar Getty is delaying the pair's divorce proceedings in a bid for a more lucrative settlement, it has been claimed.

Rosetta Millington, 30, has said the Brothers and Sisters actor will have to file for divorce himself if he is to have any hope of marrying the British actress, according to US website TMZ.

Sources claim the mother of four, a fashion designer and former model,  is moving to secure the future of her children, and her reluctance to divorce is related to their financial security.

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No divorce: Balthazar Getty's wife has told sources she will  not file for divorce even though her husband is now in a relationship with actress Sienna Miller

Should she pursue a claim for divorce, the move would separate her from any claim on the 33-year-old actor's future earnings, namely his billion dollar inheritance from the Getty family's oil fortune, it has been reported.

A source told TMZ that Getty and his powerful Hollywood family is so horrified with Balthazar's relationship with Sienna that they are giving Rosetta and the children their full support - moral and financial, despite conflicting reports that they have welcomed his relationship with Sienna.

Meanwhile, it's rumoured that the furore surrounding the 33-year-old actor's love life may be set to affect his career.

Producers are said to be thinking of putting his role on the 'back burner' for the rest of the season, insiders claim.

Inheritance tax: Rosetta, seen here with Getty in January this year, wants to ensure the couple's four children's claim to the Getty oil billions