It's far from one study. I could link a whole gish-gallup of relevant studies if people want.

Cluster B personality disorders and the 'Dark Triad' (narcissism, psychopathy, machiavellianism) are strongly correlated with romantic success, perceived threat of a face is strongly correlated with perceived attractiveness, gang members have more sexual partners than other men in the same neighborhood, violent behavior is tolerated from attractive people more than unattractive people, 39% of psychopaths in a major forensic hospital had sex with staff members, non-celibate people are on average more socially conservative than celibate people, extraversion & agreeability are largely genetically determined, etc.

None of this means 'romantically successful = bad', but it drops a nuke on the usual Just World Fallacy nonsense.