OP the point I was trying to make is that some posts are almost as if they know exactly what is going on and exactly what you should do when they can't possibly know all the facts - I do think these are mainly based on that posters own experience.
With the greatest respect to these posters there are an awful lot of people in the UK and for every bad experience there must be others who have been in your situation and it has worked out - I don't think you tend to see so many of these 'positive' outcomes though only the negative ones which is the nature of the board.
If you have doubts and read a lot of posts that re-inforce these doubts before you know it you're thinking "whoah I know exactly what is going on now the people of MN have told me!" (I think this is referred to as confirmation bias). It's hard to remain objective if you don't get the opposing posts.
I've re-read your posts and there seem to be a lot of very positive things, the main negative being his lack of availability which you've been reluctant to quiz him on? Taking these positives and your gut instinct (surprisingly reliable strangely!) you should decide whether it's worth pursuing.
I don't know exactly what he's told you but living 60 miles from his wife in a rented studio and being on OLD does sound pretty separated to me - however maybe he is hoping to reconcile with his wife, maybe the divorce is taking a long time to come through who knows unless you talk to him about it.
I don't know what age group you are but there are lots of posts about how hard it is to meet someone decent later on in life. It seems a shame to throw this away before having tried to find out all the facts. Depending on how you ended it he may come back when he's ready but equally he may think, well she's not interested and it was never meant to be and move on (men can think like this too!)
The one single bit of advice I've picked up from reading this board is to try and communicate. It is hard, and sometimes the other person won't give you all the facts, but if you're open and honest and lay your cards on the table , you could even give the conditions you would like ("I'm interested but not until you're divorced") imo that's a better approach than drawing conclusions from anonymous people speculating on a forum. Good luck!