Well of I was in your position I'd talk to her, and pick your moment, and tell her, what have you got to lose?
I need some advice I still love my ex, have done for long, but she doesn't know I still have feelings for her, I want to tell her but if I do I might mess everything up, what do you think I should do?
Erm, well it depends, do you still talk to her at all? are you friends?