It may be much simpler than that. Was the ex the dumper or the dumped? If the latter she's winding you up. Or it's just someone messing with your head, possibly bored with their life and this is their idea of amusement. For the life of me I can't remember who but someone told me the exact same tale of come-ons and pull-backs. Meetings arranged then cancelled. She turned out to have a fella and used to do it to pass the time of day when he was out with his mates. Quite simply whoever they are they are not the person they portray themselves to be.