Is ingoring a girl ever the right thing to do?

Theres this friend of mine who's a girl (used to like each other, nothing happened) that I havent really been talking to for the past couple of days. I got kind of fed up with pursuing her because she told me she was staying at a party where her ex bf lives overnight. I asked her real cool, and she almost hesitated to tell me, but then just said yea. She told me they were "just friends" now but...are you serious? Anyways. Its been about 3 days and she finally text me today saying we need to hang out soon (b/c we did alot--just doin friend stuff), and that i was a jerk for leaving the party without saying bye, and that there was drama later that night. I asked what happened, she told me, and i left it at that. We used to be mad tite, but thats all dwindled now that her ex is in the pic again, but i feel like she wants her cake and to eat it too. She always seems to pursue me when im MIA, but is that right to do to a friend? I really just wanna be like, text/hangout w/ your EX from now on since youre such good friends. I just want my message conveyed subtly so she'll lose him and start wanting me again:) Advice?