absolutely DO NOT mess with your scheduled time with the kids
bad move
but do be less available to be "her buddy"
It is nice to be buddies but she has to feel like you a hot commodity (because you are) that she made a mistake in taking you for granted (which she did) and that she might not be able to crook her finger to get you back (I hope not)
remind yourself of how great you are and what an awesome person you are and who you want to surround yourself with...what kinds of people do you want in your life...then make that happen for you
let her sit outside that circle for bit because honestly she doesn't deserve to be in the inner circle right now