I'm sorry, too, MRD, but as so many have said, you know you did all you could to make it work out--maybe in 5 years it will be obvious that this was the best decision for both of you. I'm still with my original partner after 45+ years, but I've heard divorce described (in situations like yours when there's no extreme precipitating factor like abuse or a flagrantly cheating spouse) as sadness due to mourning the death of a dream---in this case of your fantasies of growing old together, doggies underfoot on the porch.... When the marriage has been good for a long time it would be hard to give up those assumptions/dreams without sadness.
Someone I know who had been through both situations said it was much like she felt when her son came out to her--she cried, not because he was gay, but because she could see the fantasy grandchildren she's always assumed she'd have fading away (this was a while ago, before all the high tech fatherhood options for gay men). Again, as others said, at least you are lucky enough to have possible housing/job options opening up...and a wedding to plan to keep you distracted. I hope your daughter is able to have a happy wedding despite all this. My best wishes.
PS Was just reading an article (about getting over fear of flying) in which someone had taken as their mantra, What would you do if you weren't frightened?, and she was trying to do all those things. In your situation, now that you are responsible for no one but yourself for the first time in 20 years or so, what will you do? Good luck in this new chapter--and I do hope you get to find a way to finish school at some point!