I am so sorry to read that you have been treated so badly.
Men are notoriously bad at working at their relationships. Some men just like an easy liffe, and walk away if something 'better' appears to be within reach. I don;t know your partner, so i can't possibly comment.
What does seem to be the case is that he is taking an easy way out by simply cutting off all contact with you. If you are not 'there', he doesn;t have to deal with his feelings for you, and more importantly, his guilt at being so cruel - and his action is based on guilt i assure you.
It may be possible to be friends eventually, but you need an interval of time for the basis of your relationship to shift - that won;t simply happen in days, or even weeks, for either of you.
He may have simply had a panic attack, and tranlsated the 'messy' feeling of dealing with it into something he can simply jetison from his life, and 'start again' with someone new - no complications, all the fun of getting to know a new person.
It may be that he will calm down, realise his priorities, or at least that he must deal with his relationship with you, he can't simply drop it and walk away like a child with a broken toy.
Use the time to work out if you want him back, and take a long time to think about it. Beware of welcoming him back simply because it feels safe and 'secure' to take him back.
Don't make any imediate decisions bout anything. Give yourslelf time to heal and think about what YOU want.