a real bitch
A real bitch is a girl who stays with a loser even after he throws her under the bus. She's not dumb, she's just loyal.
He cheated on her, then called her a 'bimbo' in front of everyone. She just rolled her eyes and walked out.
He said he'd never come back. She still waited for him.
He said, 'I don't need you.' She said, 'You're gonna need me.'