The BBC Radio 1 DJ is said to be tired of Wood - son of Rolling Stones star Ronnie - flirting with other women and telling her what to wear, the Daily Star Sunday reports.
The pair have been dating since July, after Cotton broke off her engagement to Jesse Jenkins.
"Fearne really likes Jesse but she's getting a bit sick of him telling her what to do," a friend said. "She's a strong woman and has her own individual style. She has her own clothing range but apparently Jesse keeps telling her how to dress.
"He says he likes it when she 'dresses up' and keeps telling her how he prefers 'girlie girls' and the classy look as opposed to the grungy, alternative look. Fearne is a great-looking girl and is hardly short of male attention but Jesse gets so much attention from women when they go out that she's getting sick of it.
"She also feels a bit paranoid that he is trying to flirt with her friends behind her back when they go on nights out together. He brushes it off and says he's just chatting to them about her and trying to get to know her mates but she thinks he's a bit over-friendly."
The friend added that Cotton is also unhappy over Wood socialising with female models, claiming that the pair have argued over the situation.
"But Fearne is really keen on him and wants it to work. She keeps telling everyone she hopes this is 'the one'," the source concluded.