I think it sounds to me like you are right to leave the relationship.
Only one thing to add... when you say " Even with PTSD, you know the difference between right and wrong" - actually, you may well NOT know the difference between right and wrong. It is a medical condition in which your brain 'takes flight' from reality under certain situations - in a range of different ways.
You, yourself, don't view getting emotionally close to someone as a threat to your existence, but for someone with severe PTSD, it can be just that, to their damaged mind. Under those circumstances, hiding and turning off a phone are maybe the only things to do, in an effort to 'protect' yourself from the 'threat'.Sometimes the 'threat' can be almost anything, including daylight or any sight or sound of a person, or the noise of birds tweeting... it is a very severe psychological condition and is not simply "he's upset" or "he's been through some tough times and behaves a bit oddly". It's more like what he's been through has torn him to pieces and the fragile threads that hold him together are snapped by ordinary everyday things, each and every day.
It is very very difficult to explain, and it seems to me that you are doing the right thing for you and him just at present. Good luck with the counselling and good luck with the future
Jan
[edited to emphasise the 'you' in middle paragraph means Elizabeth, where the other 'you's in the paragraph above mean a person with PTSD!]