So there is this girl I've been fooling around with for the past 7-8 months. I've been very direct with her from the beginning that we are simply FWB and non-exclusive. About a month ago, however, she started flaking and went about 5 weeks or so without a visit. She came over today (after we went fishing) and ended up back on my couch where we were making out. Next she stops and says she can't do this.... can't hook up any more because "last time was different," that she started to like me, and can only hook up if we were dating. I kind of joked with her at that point, pushed a bit further, then kind of did a half ass Freeze Out which didn't work because she accused me of being mad.
So basically the ultimate given is to date her (which I told her I'm not ready for), or just hang out in a simply platonic basis. In my experience, it seems like woman have a 5-8 month expiration date on the FWB status. Is this just it or can I extend it and if so, how do I do it?