This is very common thing a lot of guys face. Ultimately ask yourself if the juice is worth the squeeze and if any of her actions/drama keeps you awake at night.Part of me tempted to toughen up and take her for what she offers: sex and a bit of fun once a week. Keeps me in the game for when I meet other women.
The other part just wants to get rid and move on.
If you find yourself stressing out to a point where it keeps you up at night, it's time to end it in my opinion. You don't need any gal making you grow prematurely older by giving you that much stress and affecting your health as well.
On the other hand, if you can deal with it easily and she doesn't become a crutch for you seeking out others, you can string her along for the ride. Just make sure YOU'RE in the driver's seat, not HER.