I believe you know what you need to do, both for the sake of your man friend and for you own sake!
He obviously feels very differently for you than what you feel for him. You are leading him up the garden path, or some path he doesn’t realise he is going. It sounds like he may well be oblivious to how you’re thinking and feeling about him. It sounds like he is FULLY invested while you are not!
I really can understand your fear of being on your own again after the taste of genuine companionship and partnership after being on your own for so long. Yes, that can be a bleak outlook, but you have said it yourself, you’re not being honest with this man who loves you.
If you do keep it going, for how king and for what? Until some knight appears? This hardly happens in real life, especially at our age... I calculate you are probably in your early to mid-sixties from what you say.
Let this man go — be honest with him, even though I expect it will be a very difficult conversation. I believe you have the capacity to be honest with him as, from what you say, you put others first in the past. You need to do this now as you’re not being honest to anyone the way it is.
You know, rather than focusing on your fear, you may be wiser to focus on all the positive possibilities that await you out there. But if you choose to stay “stuck” in a relationship that is not fulfilling, your emotional needs will not be available for any such possibilities.
One last point though, it may be more kind and humane to wait until after Christmas and New Year to have the conversation.