My gf of 3 years dumped me and then got with another dude the same day?

my x of 2 years 10 months was on and off with me for a whole year, dumping me every 4 months then every 2 she finally left me right before the holidays, everytime we broke up she just told me that it wasent me it was her.., and now she started hanging out with some guy she met while we were together ,some 28 year old poser rockstar whos already banging her (after 2 weeks of breakin up with me >.<) , shes only 18!, she totally controlled me and manipulated me always, the relationship sucked too cause her attitude towards me got stale and would cause arguments.. it sucks cause she blamed it all on me when we broke up, as if i was a hindrance to her anorexia recovery (yeah shes anorexic too..) but i honestly tried to always show her that i loved her and found her beautiful (she is) but she told me i made her feel gross n crap... im heartbroken and i feel guilty, is this right?