"I caught my best friend and my fiancee in bed. What do I do?"

Dear BMB readers, Two years ago, I was seriously ill, the doctor diagnosed a kidney problem, and there was need for a kidney transplant. My best friend donated one of his kidney, my fiancee sold all her jewellery and her car, in order to raise 1million Naira for the operation. I underwent the surgery and was back on my feet again, a healthy man. Two weeks ago I went to visit my friend at his house...only to find him and my fiancee in bed...ever since then, I've been rattled...so please tell me, what do I do to these two people who have spared nothing to see that I'm alive today?