I'm going to approach your situation differently than most because you said you "started to accept Christ." I'm not completely sure what you meant by this statement but because this value system was important enough to mention in your post I want to give it proper respect.
When most people say they have "accepted Christ" they are referencing a born-again religious belief. Is this your case? If so, I strongly recommend you go to your church and schedule Christian counseling sessions with the pastoral services. This will be free.
The counseling services will help you define your role as a husband and help you move passed (the justified) anger and resentment you feel about your wife's betrayal when she engaged in infidelity.
Feelings of hurt, rage and even despair are normal when a spouse has broken marriage vows. It is even more overwhelming when a spouse brings a third party into the marriage.
As the LBS you are left in a state of bewilderment. How did this happen? What did I do wrong? And, more importantly, how can I make my spouse understand how much they hurt me? They betrayed my trust. What they did to me was epic! They didn't just take away my ability to trust them---they took away my ability to trust myself because I trusted my spouse while they were betraying me.
In your case, I might be able to give you good news. The born-again Christian belief system states the role of a husband is to love his wife as "Christ loved the Church."
It sounds as if love your wive very much despite her betrayal. Your difficulty appears to be how you can (justifiability) move passed your anger and hurt.
Again, this is where I think pastoral counseling might help. They should be able to give you tools to help set boundaries when dealing with your wife while communicating your love for her.
