Gosh, that is an incredibly painful place to be.
I look back and see how I was tortured with suspicion but somehow I just kept blocking it because my wife had looked me in the eye and said, "just friends". I mean, it is insane in retrospect but I believed her even while some deep down part of me knew it was mad. So that split inside me was torture itself though I didn't understand it at the time. Your husband is reacting with anger instead of helping you with understandable pain. He is failing you on that level even if that is all it is. But you are right, I think, those behaviours you are describing of picking fights and drinking are all too consistent with an affair to ignore, and there is clearly history there. Some people think they can lie their way out of it, as though life is a series of episodes like a TV show and as long as they manage to fool you in season three, episode four it just won't come up again in season six. So your husband thinks he can lie and as long as the lie works it will be okay. Your questions: It does not sound like he will tell you on his own. Yes, the horrible gut feelings will keep coming back. Should you tell him what you know for sure? I don't think so. I think that you should tell him you are giving him a chance now to come clean with everything, that you know more than he realises, and that if he isn't honest now your marriage is in deep jeopardy that it might not come back from. Then listen. He will say, "what do you actually know???" and you will say, "never mind what I know, tell me everything now." (Otherwise he will just lie enough to address that one thing.) And then if he sticks to the "just one time" story you will know he is still lying. And then do your best to say, "okay, is that really the best you can do?", and then go be by yourself and think about what to do next. Those are just my thoughts, there is no right answer and your gut is your best guide. Good luck, I know what you are feeling.
Maybe it is okay, maybe it will be okay.
BS, d-day Feb 2017, 16 mth affair.