I'm sorry you are faced with this difficult dilemma.
There's a lot here in what you wrote. And I could write a lot in response to it. However I don't want to write a book here. And I doubt you would want to read it if I did.
I guess the one thing I can say is that, since your bf is approaching 30, it may be unlikely he's going to change significantly. So my thinking is... what you see may well be what you get, as the saying goes.
If you're less than happy with the way things are now, marrying your bf... or at least staying with him for the long haul... is only going to bring you more of what you're already experiencing.
I know you wrote that you love your bf, you don't want to hurt him & you're concerned about what will happen with him if you leave him. But you have your own life to live. Plus, at least in my experience, things don't tend to improve once a couple marries. If anything, problems become amplified... especially if children enter the picture.
And along those lines, one thing you mentioned that would be of concern to me is with regard to your bf giving you the "ice treatment". This is typically considered to be a form of emotional abuse. And so, at least from my perspective, it does not bode well for your future if you stay with this man. Unfortunately I don't have anything to offer wiith regard to your concern you may not find another relationship if you leave this one. That is a potential problem you will have to weigh in the balance as you decide how to proceed here I'm afraid.
Here are links to some articles, from PsychCentral's archives, that may be of some help to you in figuring out where to go from here:
https://psychcentral.com/blog/before...e-5-questions/
https://blogs.psychcentral.com/life-...-with-someone/
https://psychcentral.com/lib/what-yo...ving-together/
https://psychcentral.com/blog/21-war...-relationship/
https://psychcentral.com/lib/signs-y...abused-part-i/
https://psychcentral.com/lib/signs-y...dium=popular17
https://psychcentral.com/library/domestic_quiz.htm
You brought up the question of whether you might possibly be on the autism spectrum. So here's a link to a quiz you can take that may be of some help in further determining if you "qualify":
https://psychcentral.com/quizzes/autism-test/
My best wishes to you...
