No contact is about wiping the slate clean so that you can forget about your initial reaction to the breakup. However, no contact is there to help you get through the breakup as painlessly as possible. It is not a tool for punishing your ex, nor should it be used solely with the aim of getting back together.
You are only four days in. There is a long way to go. Also, don't forget that there are several elements to no contact. You need to focus on yourself.
Finally, if your ex cheated on you, why would you want him back anyway? Sure, it hurts, but have some self-respect. You deserve to be treated far better than that. It's his loss, not yours.