Most Helpful Guy
You might have a case but, let's face it, this is what marriage is for... Stuff like this is WHY people get married. So, while I am optimustic that you might gain some visitation rights, I doubt you will without a sympathetic judge who might also have to be somewhat of an activist.
Most Helpful Girl
No you have no legal rights, your not a biological parent or an adoptive parent. Your ex is one stubborn selfish asshole though. He made you a mother figure to his daughter and do all those things for her and grow a bond, just to slam the door shut and cut off all access. That poor daughter must wonder why she can't see you the same way your wondering why you can't see her. I would say the only time you would be able to see her again is when she is 18 and thats if she remembers you or doesn't already have another woman manipulated into the same path as you were. I wouldn't get back with your ex or talk to him at all again, he seems like the worlds biggest asshole for what he did. You already can't reason with him to even see the daughter for her sake, I would just give it up. Its gonna be hard but you are going to have to move on. I'm sorry. :(