Originally Posted by opalescent
I have to agree with kkxvlv. Some people will not leave a relationship until they have someone else lined up. Your ex - and that is who she is even if neither of you acknowledge it - is looking for her next partner. There is not much to discuss or wonder about - except maybe why both of you were willing to accept this for so long.
Lots of people do this as a form of "serial monogamy". I had one or two relationships where we "broke up" but would still see each other for sex until one of us found something or someone that captured their interest to a greater degree. And mine had nothing to do with issues over nonmonogamy.