Its not easy I tell you. But you can do something. It wont be easy nor painless because believe me, it will be more hard and difficult to face the facts. But hey, you just really have to be strong enough to pull yourself together at this point.
Do everything you can to win him back it doesnt matter if your doing it over and over, dont stop as long as his also giving in someway, meaning he still wants you to help him hang on for both of you, BUT, if you feel like your the only one doing the things for both of you, and yet your hurting at the same time, just keep doing it, over and over, (you may call out friends for support, that is a big help in this stage) that time will come to you, when you can say your tired and you couldnt feel any pain anymore. That would be the time that you can just walk away without care. That moving on is just right there. Youll be alright after all that. Im sorry for what happened to you. Hope youll end up happy whatever it is you feel like ending up and have a peace of mind.