THE model-actress and the rugby player split up last week after dating for two years
It's claimed the couple went their separate ways after arguing over Kelly's ongoing friendship with her former flame Danny Cipriani.
A source said: "Even though there was nothing going on while she and Thom were together, Thom hated the fact she was seeing him and Kelly refused to end their meetings.
"After one row too many the pair decided to end things."
The insider continued: "She's been leaning on Danny since the break-up and, while she's devastated, she knows it's for the best."
Kelly was pictured out in London with Cipriani last weekend.
Thom, 27, is said to have already moved out of the couple's home, while Kelly, 33, has jetted to Miami for some winter sunshine.
She tweeted: "Arrived in Miami!! Lovely to be back! X."