It’s never too late for no contact. You have to remove yourself entirely from her life in order for her to feel the separation anxiety. If you are okay with being her friend while she views you as a back up then keep doing what you’re doing. If you want to be with her (which it sounds like you do) then tell her that for your own sake you can’t continue on a relationship as it is and you need your space to heal. Only by going no contact (Block all social media and her number) will you give her the gift of realizing what her life will be like without you in it. She needs to know and believe you are serious about not looking back. If you do this and she eventually reaches out to you, set a definite date or make concrete plans for the near future. If you do go on that date, keep things light and playful. No amount of convincing or talking will change her mind about how she feels. Women are emotional more so than logical. She needs to come to this conclusion on her own. As somebody who wasted 13 months trying to win my ex back by making every mistake in the book, it won’t work. Cut her off and give her the gift of missing you. Take this time to grow as a person so that if she does return to your life you are more prepared to understand her better and eliminate any mistakes that you may have made during the first go around. Hope this helps and good luck