What are the signs you're being used as an emotional crutch by someone?

[Anonymous]

As the question states, I am dealing with a woman that I suspect might be using me as an emotional crutch rather are than being genuinely interested. What signs should I be looking for?

[yaddayaddayadda02]

Are you having sex with her?

[Asker]

Nope, so here's the cycle. She'll date me, we'll start getting physically engaged she'll admit interest then back out - at which point I assume she's uninterested and carry on with my life but she still tries to keep my attention. I refused to give her any, and let her chase for a while since she was acting hot-cold. We go out again, and she comes on proposing sex super strongly, but then backs out again.

At which point I told her I am done with her. Trying to figure out if she was just using me as an emotional crutch.