The estranged wife of Sienna Miller's lover Balthazar Getty is not gonna make it easy for the unpopular couple to be together.

The Brothers and Sisters actor will have to file for divorce himself, after Rosetta Millington made it clear she was holding out for the best financial settlement possible.

Sources tell TMZ that Rosetta is keen to secure financial security for their four children.
 
If she initiates divorce proceedings, she will be unable to get hold of her wandering hubby's future earnings – including that billion dollar inheritance from the Getty family's oil fortune.

And to make matters worse for Sienna and her man, Balthazar's  powerful family are said to be fighting Rosetta's corner.