Hi RQ, sorry you've had such a worrying time. Things may be in order or they may not be, but you need to know and get sensible hard facts, so trace him. B4usearch is down at the moment but tracesmart is still online and you only need his name and town to check his address out on the electoral roll, so that should be easy. You could always go the way of agreeing to open a joint account with him, go to the bank, wait for him to whip his ID out at the interview and then say "oh ****** I've forgotten my drivers licence". DON'T open the account. He's got no chance of opening an account without photo ID, so that's another method of finding his addy if he doesn't show up on the electoral roll.
Call his company and ask to speak to him, if he answers hang up, if they are clueless about him, you have a problem. If he's not there, gain as much info about him as poss from whoever answers the phone.
I don't think you necessarily have a problem, but I do thnk you need to be very careful. I'm not big on snooping on partners but I think you have sufficient cause to need to know a few things about him before you get in any deeper.
There are some other things you could do, but I'd stick to these for now and depending on how you get on and what you find out, you can take it from there.