The 22-year-old actress is believed to be ready to move out of the couple's Cheshire home that they purchased when Sinclair signed for the Manchester club from Swansea City last summer.
"Helen and Scott break up every other week," a source told The Sun. "It is something all of her friends have got used to. But the fact that she's told close pals it's all over is a new step.
"She loves Scott but thinks breaking free will give her a new lease of life. The fact she is talking so publicly about 'the end' means this could be it for good."
The pair have been together for around four years.