Thank you, everyone, so much.
Thank you everyone for your kindness and support. I wasn't sure about coming to the internet to talk about this, but as my best friend pointed out, she can tell me things until she's blue in the face, but I'll take it best from people who've gone through all of this themselves, and because they don't know me won't have any particular interest or agenda to push on me.
The shock's still sinking in, and my main feelings are still grief, self-blame and denial, but I've accepted that it's over. We've arranged to meet face to face in a couple of days, and by then I think I'll have gathered my wits enough, and summoned up the courage, to ask the questions I need to ask. I have a horrible feeling he's going to try to minimise the part that his alcoholism has played in all of this - "No!" I hear you say, "Really!?" - and I'm preparing myself for that, by reading a lot of the stuff on here, and other sources on the internet.
I am emphatically not blaming EVERYTHING on his alcoholism - if he doesn't feel like we're right together then he doesn't feel like we're right together - but it's more a matter of finding the right words to say, so I don't come off as though I'm being vindictive or deliberately hurtful. He is well aware he has a problem. The more I think about it, the more incidences I think of where in retrospect it's clear he had been drinking, but he either lied outright when I asked him, or I didn't ask the right questions to get the right answers.
Fortunately due to our financial and property arrangements, moving out and dividing the assets isn't going to be as horrendous as it could be. I plan to be fair to him, and I know that he will be fair to me.
Also, I am going to see if I can meet with his mother face to face, to say goodbye and answer any questions she may have. She attends Al-Anon meetings because of her daughter, and even though it wouldn't be right to go to the same meeting group as her, I know she'll help me find one.
I obviously feel sorry for myself and my ex that this has happened, but in a way more than that I feel sorry for the poor tenant in a property we own who just renewed her lease and will probably be receiving her 90 days notice soon in 2011, and even more sorry for my ex's mother. She's had to deal with both of her children for so long. Several times when we've had coffee together, and she's talked about dealing with her daughter's alcoholism, she told me about something Al-Anon teaches, which is sometimes when you love someone, you have to detach, and love from a distance. I'm the one who's been detached from, and thrown out of the "circle of trust", but that's starting to make a lot of sense.
Again, thank you for your advice and kindness.