Well here's my opinion as a female INTP.
INTPs are scared of relationships, period. They are scared of feelings, of committment, of other people needing emotional support... Basically everything a relationship is. They also don't really need other people. So your guy has a fundamental disinclination for a relationship with ANYONE.
It's not about whether he likes you or not. He does, trust me. But does he need you? Sometimes. But sometimes not. One thing you are going to need to figure out is whether you can be okay with being his "sometimes" person. If your heart is going to be shattered every time he walks away for time somewhere else, (whether it's someONE else or just personal space) then it just won't work.
This isn't to say that you can't find a common ground to work with, however. One plus about INTPs is that they are good at understanding things if they are put in an analytical form. It may still be difficult for him to explore feelings and needs, but that's something I highly encourage you to do with him. I recommend lists. Lists of needs and expectations may help bridge the gap between the "scary emotional stuff" and tangible things that he can grasp.
Whatever you do, don't wait around hoping for him to change. He will never be able to fill all of your needs, even if he does improve in some areas. The question is, will you find someone else who is better at filling them, or can you find ways to fill many of your own needs yourself? (eg. a best friend for emotional support, a dog for a constant companion...)
Lastly, in defense of INTPs ... We aren't actually cruel and heartless. Our needs just look different from everyone else's. We have feelings, and we don't want to hurt anyone, but we are REALLY terrible at emotional support.
Anyway, I hope this helps. Good luck to you both.