Hi im trying to find a the title of an mf book that is probably about 15 years old.

Its about a woman who has a stalker. He's convinced everyone they are a couple to get her to go out with him ,turned up at her family home as if she had invited him to family dinners etc. Everyone believe him no matter what she says to deny it. Then he leaves her alone for a while. Next thing she knows he had come back and is dating her sister. The stalker has told everyone she's now jealous of them. During a family meal he tells everyone he and her sister are getting married, but quietly told the main character he will harm the sister if she doesnt play along or do as he says. Having enough she leaves for the garden for a Breath of fresh air to calm down, but the stalker follows her threatening her. She climbs the fence to get away and lands in the neighbours bumping into a house sitter. And thats who she falls for. The rest of the story is this stalker trying to split her and the house sitter up.