Conversation with anger

It's complicated. It would be normal to be paranoid and jealous. Huge. Just talk about it with him. Start the conversation anywhere. Have the conversation anyway but ... just know if you don't bring this up and even if you do bring this up that asking him to explain it DOES NOT mean he can put words to it,,, meaning - please don't confuse his inability to explain with guilt or confession. This has got to be difficult to explain and communicate with wisdom and words are extremely likely to sound typical and suspicious. Please don't ask questions in a way that will lead you straight away to buying a shovel. 
This last sentence was a joke that crosses ones mind out of discomfort. 
Only kill him if you don't have any other choice. That second last sentence was meant to be a joke. What?!? 
Best of luck. Yes, very good and yet tricky and highly personal and subjective question. ,,,,,,,,,,,,,,,,,,

Best advice I can think of for this - bring it up and laugh about it with him as much as possible. Laugh about each "hypothetical" scenario. Yeah, best approach. That is my recommendation.