The 42-year-old actress ended her seven-year marriage with the 'Miranda' star after he confessed to a one-night stand while filming 'Gothica' in the US earlier this year but, despite failed attempts to patch up their relationship, the blonde beauty has asked to legally end their romance.
A source told The Sun newspaper: ''Tamzin desperately tried to make it work.
''Tamzin has cited adultery, so she will have a huge advantage when it comes to negotiations. Tom's a reasonable bloke and as it's pretty cut and dried they could be divorced within months.''
Tom has moved out of the family home, but the pair - who have daughters Florence, four, and one-year-old Marnie Mae together - have vowed to remain on friendly terms for the sake of their children.
Just three months ago Tamzin - best known for playing Melanie Owen in 'EastEnders' from 1998 to 2002 - said she was ''very proud'' of her husband, who has daughter Nora from a previous relationship, and was convinced their marriage had lasted so long because they rarely bicker.
She said in June: ''He's [Tom] doing really well and ... it's all pretty happy days at the moment. We're not big arguers.''