How about sticking him in the friendszone and detaching a bit from the emotional clutter?
I hear you about the feeling of getting older and wondering if this is as good as it gets in terms of being tossed crumbs and the field seems like it gets smaller and smaller if even existent. And frankly, who wants to keep going through it?
If he's not devoted to establishing a life together....he needs to get into the friendzone. And if he's not even a good friend then he needs to be cut loose.
I get the back and forth is ambiguous...
You don't even need to announce this to him. Make that inner change with your heart and your mind.