My husband just told me that he had an affair. With another man. I feel like my world just ended. What do I do?

So sorry to hear that. I realize that It is very rough for you but this is not the end of your world. He has committed adultery not you so hold your head high. Get an answer out of him regarding his affair. If it was by mutual consent then seriously consider divorcing him. You deserve someone better and not a cheater!!