Know when to let it go.
Regardless if you explicitly tell her you're not looking for a commitment, and openly acknowledge you're dating other people, she may still get attached. Emotions don't follow the rules.
If she has feelings you can't return, boss up and end things. Sure, it feels good to be loved. It's nice to have someone who will spend time with you, have sex with you, and not require anything of you. But if you sense she's only begrudgingly playing the part in return for something you'll never give her, let her go. If not for common decency, then for the fact that the aftermath will be ugly.