Do ex girlfriends have a 6th sense?

I've been seeing this guy for about 4 moths in a casual relationship. He admitted he still had some feelings for his ex but hadn't seen her in over 3 years so thats why we kept things casual. (even though i think after 3 years you should be well on your way getting over someone) Anyway his ex has now turned up. turns out the bloke she was with was physically abusive towards her so they guy i was seing stepped in and sorted things out so he wouldnt bother her anymore. I've since been told by this guy he wants nothing more than just friendship because he wants nothing to complicate things between himself and his ex and im so gutted. Apparently she tried to kiss him and its made him think about things. I'm so gutted cause ive grown really fond with this guy. Seems im only anygood as a stand in till the ex comes back. Back to the original question, this isnt the first time an ex has reappeared after years of being away and been given the "your great and wonderful but i just want to be friends" speech so do ex gf have a 6th sense cause they always reappear after i come on the scene. Thank you very much .