Big grizzly hugs to you, and CONGRATULATIONS to your daughter on graduating!!!
I'm very impressed with how much work and thought you have put into this decision. And as you say, it isn't a selfish one -- it's a decision that values you and your RAH as individuals who have a right to pursue happiness along different paths.
I'm sure it won't be a walk in the park -- divorces seldom are -- but I'm also sure that it will be much easier because you have put so much thought into it. You know that what you are doing is the right thing, and that makes putting up with the bumps along the road that much less stressful, I imagine.