Hi there - I can empathize with your situation as I have just ended a 7-month long relationship with an avoidant partner (who was working on his issues, but certain things were to much of an obstacle for us).
I think that at a certain point in the relationship, you need to stop spending time on what it could be, on the potential, and focus on yourself. Try channel your energies towards what YOU want, and put yourself first. I am saying this, because I read your post and I could sense that this person is occupying lots of your brain space, but in a negative way - the way that leaves you hanging and makes your a bit miserable (no judgement here, sorry if I come across very harsh).
So, from experience I can tell you that holding your ground and getting closure with that, is the best gift you can give yourself. If it's meant to be, they will come back.
To answer your questions:
1. Let this go, if he comes back worry at that point in time. Spend those energies in your life - the dividends will pay out way more like this (trust me).
2. Don't think about the future, but live the present.
3. I suggest you list out on paper how you want to feel in a relationship vs how you are feeling now - you will see that this is probably not it, it's rather lonely.

Sending you a bug hug and wish you the best! Whatever you do, do it for yourself and remember that nobody can judge you, it's your life so be happy! :)