Too much there. I'm very sorry. A relationship shouldn't be filled with so much doubt, jealousy and insecurity. I agree with a lot with the other members especially the points made by SGH and Bluecastle. There are a lot of red flags that just can't be ignored and your feelings towards a lot of the information (no matter how much you want to rationalize it and have everything perfect) is not reconciling with your idea of what a relationship should be.
I specifically don't feel like he's processed enough at all and if he can't tell the difference between any of the women he's known or if he isn't able to speak about it with some candor (those differences and make you feel special as you ought to feel special and present in his life), it's very telling what space he's in. I also don't encourage you to pry any longer because in your insecure state, you're going to come across as threatening and it won't be a safe place for him to open up. It becomes a very negative and unhealthy cycle between the both of you. Both of you need to cool it and acknowledge the past is in the past.
I don't think the cheating history is worth focusing on (it's knowledge and information but it's not sane to focus on it). It's nothing that you can change and if you focus on it you're also focusing on something negative and destructive, something out of your power to change and you simply don't have enough insight (you both don't seem to have bonded in your love or your love isn't deep enough to provide any understanding of why the past occurred). In other words, this is opening up a can of worms or picking a battle that you cannot win. To me, it holds totally no value - psychologically, emotionally nor does it add to your health or wellbeing. You are also allowing someone's past to dictate your future decisions. To me this would subversively rob me of some power I'm not willing to relinquish. That's just not who I am and I don't think it's healthy.
If I were you I'd be focusing more carefully on the way the relationship's dynamics are presently and focus on your present tense and your reality right now, the way he makes you feel (or doesn't make you feel), the direction the relationship is headed in and what you want out of life. If this isn't for you, you then make the decision to end it on your terms.