He's been 'unlucky in love'. [=he has had a series of bad romantic relationships]
She was 'unlucky' enough to get a flat tire on the way to her job interview.
He thinks it's 'unlucky' to have a black cat cross your path.
(..) - We're unhappy... - How unhappy? - Too unhappy... That won't do When you are blue, just knock on wood... - How unlucky? - Too unlucky... But your luck'll change If you'll arrange to knock on wood... - Who's got nothing? - We got nothing... (..)1942 Casablanca