I doubt you are going crazy! I'm sure thinking about your wife having feelings toward others is a challenge given what you are going through. As you identify here, this is likely some mental "smokes and screens" to divert you from the pain. I can only say that it's important that you be easy on yourself, allow your thoughts and feelings to be what they are, and know that just as everything in life does, these will come and go. Know that any thoughts or feelings of "jealousy" do not detract from the great love you shared with your wife.