Should i leave her life....?

I want her to be happy, she deserves it and I deserve to be shut out of her life. I'm giving up on her and walking away, even though it'll probably snap my heart into pieces. She doesn't wanna pick up the pieces. She talks to my family and loves her boyfriend. When we see each other we get on like a house on fire, but when I try adding her on Facebook she doesn't accept it. She was always nice to me and now I'll leave her behind. She once called me important in her life and said she doesn't want to see me leave, but there's no point in me staying in her life, if she doesn't talk to me.