Mike. I want to remind you that relationships can strengthen after an affair. Your wife will be angry for a long time, you can expect that. But before she can move forward you MUST let her express all of that anger and confusion. You also need to acknowledge that you've shattered her dreams and feelings of security. There are many books on surviving after an affair. I'd definitely recommend putting your marriage on project status and REALLY focusing on improving it. Adding another woman (who will come with her own luggage, just a different shape and color, lol) will not solve your issues. But that is not to say that polygamy is forever out of the question. It's just out of the question, for now.
Best Wishes, Mike! Please update us.