Welcome to HCM
We understand your concerns
I went through your description. I suggest you to be calm. There is nothing which can harm except your negative thinking. Your boy friend must be having his own reasons for having such discomfort in his testicles. He will take care of it. when he is OK, he will come back to you.
Instead of supporting in his difficult times, you are accusing him of cheating. I suggest you not to think that way because you are the person who is going to get affected with such thinking. What are you going to do if your boy friend has another affair? Just accept it. Don't doubt.
You might need psychological counseling
., I am more than happy to provide telephone psychological counseling through healthcaremagic. Contact me through customer care, www.healthcaremagic.com.
Hope this clears your doubts. Available for further clarifications.