Your ex will fill a void in you that needs to be filled by someone else.
You sound very much like me a few years back. Same patterns of not breaking off completely and not moving on. I no longer have any connection with my ex, period. I finally cut off all ties with her, threw away all objects and photos (ok that was hard) of us because it kept false hope alive and kept me from pursuing and finding a real relationship with someone else. After years of on-again-off-again relationships it HAD to end. She was filling a void in my life (and vice versa) as friend/ girlfriend/ whatever... that needed to be filled by someone else, someone who was a better match for me. Like someone else said, you can't really change someone, especially someone around 30 years of age. Staying friends or a sex-only relationship rarely works. There will always be an underlying issue that will get in the way of forming other healthy and newer relationships. Your ex will fill a void in you that needs to be filled by someone else.
I took my losses and moved on. We then tried to be "friends" but that was a HUGE mistake. I lost years focused on false hope. The worst regret I have now is having spent so much time trying to force our relationship to work, when I knew in my heart it was over long ago. Time is truly my most valuable resource, and time gets more critical when I got past 30 and still want the whole family and kids thing. Your ex will fill a void in you that needs to be filled by someone else.
My opinion is to find someone else, date and befriend lots of people - when you find that girl who is the one, your ex and her relationship with her will become very clear and you will wonder why you put up with so much unneccessary heartache. It will hurt, very badly, but break it off - the hurt is only temporary though. 9 years is a long time to be trying to still work things out. Sounds like you are trying to force things to work like I did. Your ex will fill a void in you that needs to be filled by someone else.
Oh, and... Your ex will fill a void in you that needs to be filled by someone else.