What a devastating experience for you. Your question to me is how can you make a decision when you are still so hurt. I think you can't, not just yet.
First we need to discern the forest from the trees. To do this, you need to have a series of heart to heart talks with him in which you both come totally clean with each other. Above all, he needs to become conscious of the reason why he cheated. To do this he needs to understand that affairs don't happen by accident: an affair is a symptom that something isn't working in the relationship. Cheating is ultimately an act of aggression that says, 'I'm finding somebody else because you aren't meeting my needs '
In order to move forward, he needs to tell you everything that angered him before and that angers him now. In short, you need to know exactly what you are doing--probably without even knowing it--to drive him away. Likewise, he needs to tell you what you can do to make him happier in the relationship.
Then reverse roles. You come clean with him. Tell him exactly what he is doing--probably without even knowing it--to drive you away. Likewise, tell him what he can do to make you feel more connected to him.
When you have the facts, you both need to work on resolving the issues that are on the table. At the same time he needs to resolve two serious problems. The first is that he doesn't communicate his angry feelings directly. I think his tendency is to keep quiet when he's mad. This stored resentment builds and eventually when the pressure is too great he'releases' the anger by paying you back--in this case through cheating.
He must learn how to talk about and resolve his angry feelings. Until he does, you aren't safe. The other thing he needs to work on is what appears to be an impulse disorder. Here I refer to his tendency to act out in order to release internal emotional pressure. As you can see, his two problems play into each other. Swallowing his feelings creates a build up of emotional pressure and then his inability to tolerate his feelings causes him to discharge them in destructive actions.
In order to feel safe to start over with him, you need to be sure that he has learned how to talk about his feelings and not act on them. This type of work is going to require outside help. In time, you will see the changes in him in the way he deals with you day to day. You will see him facing his feelings and talking with you rather than running away.
When you are certain that he's made lasting personality changes, you will then be ready to make a decision about your future.