Hi jen45,
sorry I couldn't stick round yesterday (got a 8mth old baby boy, teething badly) but I just wanted to say to you, I really hope you listen to what everyone here has said, stay strong and get away from this guy.
It's going to be hard, he is going to put on nice displays on the run up to the 30th, but it's fake, fake, fake. Once you're in Canada, it'll be the same old story again. You sound like a really nice person and you deserve better. I did assume that you both were much younger, I think the advice an earlier post said about getting counselling is a really good idea. You need to break the pattern of falling into emotion blackmail and co dependancy etc.
You certainly sound fed up with following him from move to move. It must be so stressful, once you settle he's off again.
Just stay put, do it carefully, he seems to take you for granted and will probably be very surprised. Everyone has a limit, you have reached yours. I would keep it really simple, just say you can't leave you sick mum and repeat that over and over, don't get drawn into a fight over it.
You made a mistake marrying him but you can turn it around. Reclaim your life. Good luck, I really wish you the best.
By the way, I never answer the relationship threads, exactly because I would never want to say something as frank as I have here, but I really feel for you, don't pass yourself off out of fear that you are 45, you have your whole life ahead yet. This is just a bad mistake that you will get over given time.