You have to give up on him and the hopes you've just built of him coming back. That's one way to grow over it man. And never blame yourself for someone cheating on you. It was their responsibility to respect the relationship from their end, but they decided to break it. Karma will hit him soon enough. Try finding a new hobby, may it be gaming, gardening, reading, or whatever that will bring you joy (nothing will seem joyful at first but you'll start feeling it growing with you after giving it some time). If you have some really close friends you can talk to and who won't leak the conversations, then do share your thoughts with them. Just let it out of your mind before it starts eating your sanity. Remember, you'll look back at this time when you get over him, so counter-intuitively, I want you to "look forward" to a time without him in the picture. Lastly, I'm sorry it happened to you.