Run, I can only imagine the emotional turmoil you must be experiencing.
First of all recognize that you're in a vulnerable state right now, and avoid anyone that makes unhelpful comments like 'you deserve it.' Your relationship is between you and your wife, it's not anyone else's business and people who want to take sides is certainly not helpful in an effort to try and save it - that basic dynamic is one that causes division. Opinions on this type of situation isn't all that helpful as far as I'm concerned, because what's most important is YOUR relationship.
As far as forgiveness is concerned, I have to say it never comes from ignoring the issue. I mention this only because often it is so painful and there is such strong emotion around it that it is never seen completely in its entirety, so it's a matter of how thoroughly it is seen and dealt with. To put it another way, don't try to jump the gun - you'll go through it in your own time at your own pace.
True union with anybody involves the heart breaking open, whether it is in a romantic relationship or otherwise, and while it's not necessarily a painful experience there IS that openness - the pain comes from the violent suddenness of a breaking, so to speak. You can tell when that's there because there is a sense that the other actually shares your pain, rather than feel bad about your pain which is just their own feeling. If the pain is so strong that it feels like it kills you, then a true and full sharing of that is reflected in the other experiencing it the same way - because it is a tear of the relationship, what you have together. I mention this because it would allow you to distinguish between a 'breach of contract' and an actual break of the bond between you, which you obviously feel.
So beyond dealing with the situation (and by that I don't mean analyzing it psychologically, just seeing and meeting it) forgiveness involves that kind of opening to each other. But again, don't beat yourself up over it - have compassion for yourself and whatever feelings you may have around the situation. If anything recognize when there is the butting in influence of friends and family and distinguish that from people who give you support and help you put things in perspective. It's not about anybody else's opinion on what should happen, which direction you should go, it's about supporting you in your efforts in dealing with the situation.