How should i handle this?

long story short been friends with this girl 6 years we had a fling now its back to being friends and honestly feel like im giving into this frienship more than i get and shes taking advantage. i kind of want out of it but at the same time we have alot of history. i want to back off and leave it to her to choose where this goes and i dont care how it goes from there. problem is idk how to say it maturely lol. im sure she doesnt have any feelings for me and i just to put this friendship or whatever it is on her and back off. basically if she wants to remain friends i want her to prove it and if not then well thats one less problem i gotta deal with. any ideas?