Thanks for the A2A, but I’m just as baffled as you are. I would normally counsel patience and acceptance, but in this particular instance, I have to go with the ladies here and urge caution. Men can be real slimeballs.
That said, it doesn’t seem like you don’t seem to have a screaming gut that you’re trying desperately to ignore. That seems to happen a lot here. So much misery happens when people don’t listen to that little voice telling them to run away.
It’s possible that a) you’re misunderstanding him, and he’s not as eager to settle down as you have come to believe or b) he’s just at a phase in his life where he knows with dead certainty exactly what he wants and doesn’t want to wait around for it any more. If that’s the case, and you want what he wants, then the plan would be to use this as an opportunity to make sure that he is what he says he is, that he doesn’t have another wife and kids off in another state somewhere. Once you’ve satisfied yourself, jump in with both feet and enjoy your new life together.
I personally would never consider marrying someone if I felt like I needed to do a background check on them before I could trust them, but you might want to consider it. If only for your peace of mind.