Hey JR, I think it's very healthy to acknowledge that loneliness - it's all part of accepting your situation as best you can - and then figuring out how to make the most of your life with that knowledge well in hand.
My S12 is leaving in a couple weeks to be with his mom for the school year - it's already tearing into me and making me very sad - so I just keep reminding myself that I have to live in a way that once he's with me again - whenever that might be - he'll be with me as a complete, healthy, and positive force in his life. I know you know this - and that you've already done a ton of work to get there yourself - I just wanted to let you know that, indeed, you're not alone in what you're going through. It's such a tough part of all this drama - having to figure out the best way to protect our children.
Like you, I cry a lot less than I used to - but these days, I find that when I accept the tears - and just let them do what they have to do - I always feel better afterward. During the sadness, it sometimes feels unbearable - but it always gets better.
