Mariah Carey is devastated that Nick Cannon is dating Nicole Murphy.

The '#Beautiful' hitmaker, who split from the 'America's Got Talent' star last summer after six years of marriage, is reportedly very upset after he was spotted celebrating Valentine's Day (14.02.15) with the former 'Hollywood Exes' star at the romantic New York restaurant Tavern on the Green.

A source said: ''Mariah thinks he's just rubbing Nicole in her face. She'd heard through the grapevine that Nick was seeing her, but Mariah thought it was low for him to parade her around on Valentine's Day.''

The 44-year-old singer still has feelings for her estranged husband, with whom she has three-year-old twins, Monroe and Moroccan.

The insider added to Life & Style magazine: ''Part of Mariah still loves Nick. She keeps tabs on him and just can't seem to let go.

''She hates being alone and single. Now there's evidence Nick has moved on, and it hurts deeper. Worst of all, Nick has told friends he could see himself proposing to [Nicole] someday! He's crazy about her.''