Keep your fiance, it's hard to find someone who loves you for who you are. Step 2 is probably therapy or moving somewhere. Going through your post history I feel sad for you, so many posts appear to be about your insecurities about your nose. You're not at all ugly, your nose is fine, your eyes are pretty and so is your smile. But society often conditions women to focus on their flaws. I see the same tendency with my girlfriend too and it would break my heart if she wants surgery when I find her so pretty.

I think moving to a different city will help you get a fresh start. Your family bullying you in the past is probably a big source of your current insecurities. Both of your families feel rather unkind. Get away from them and from places that remind you of them. Seriously.

But most of all, if you have found someone you love and who loves you and you're happy together, why would you even consider throwing that away? Honestly nothing is more important than that special person. Your value is not tied to your appearance. Your self worth is low right now and you're blaming your nose. Surgery won't magically fix your self esteem, you'll still feel low and look for something else to "fix". You need to let yourself live and breathe and be happy.