. 1. But for her, I wouldn't be who I am. But for her, I wouldn't have been who I am. -- The second one is illogical and should not be used. I can be fixed this way: But for her, I wouldn't have become who I am 2. What's the difference between "who I am" and "what I am"? -- Who am I? I'm Mister Micawber. What am I? I'm a moderator. .