The 26-year-old singer strives to be true to herself since being stuck with a negative boyfriend.
After learning valuable lessons from the experience, Ellie urges people not to let others have such an effect on them.
"You should never change for anyone. And I say that because I've done it before; I've changed for a man. I was with a guy and there were things that he didn't like about what I wore or the way my hair was," she recalled to the January edition of UK magazine Cosmopolitan.
"I was so, so in love with him that I'd have done anything. I look back now and think, 'What an idiot!' You only realise when you're out of it how someone can have a hold over you. He treated me horrendously and I just didn't help myself; there were friends around me who'd say, 'You do see what he's doing to you?' But you don't at the time."