Wow. Sorry to read that bud it's never a good situation to be in. I think most can relate to this situation at some stage in our lives. No offence but she sounds like a right spoiled selfish Ar##hole. She will do the same to the next guy although it's not nice to read how happy she is. For all you know it's a smoke screen so people see it but it may not be 100% true. Focus on yourself mate and get back on track. Keep busy and don't let it get to you. Not all women are like that, granted they are ALL mental but they just vary in level being a muppet. Chin up Mate and hope it gets better for you. It will there's no mistake about that bud. To be honest with it ending you dodged a bullet she could have ended up pregnant and seen her true colours of selfishness for years to come.
Beer and strippers for a few months mate and knock a few angry wanks out it will all be fine dude.