Be strong...
You will go through many phases of healing, it is different for everyone. For example, at first you might experience shock, then rationalize the event-like "all men do that," then you might become jealous of the affair and try to win him back by trying to change (such as, try new things in the bedroom), then you will be sickened by being jealous and trying to change yourself and then upset with yourself because on some level you blame yourself, then you get really angry and beat him up with words every chance you get, then you begin to feel bad for him, then you hate him again, then you feel bad again...
I have been where you are and my advice is to hold on and be patient.
Marriage is worth fighting for; so don’t be afraid to fight for it and if you are anything like me you will be fighting more with the “proud woman” within you more than with your husband!
Marriage can only work if BOTH want the same thing! I hope you and your husband can work things out because too many are willing to just throw it all away these days!