Most Helpful Guy
You had a right to feel unsettled - becuase I think he's screwing you over.
That 'Chemistry' you think you have is something he has engineered to make you feel like something is there/was there/could possibly be there/will be there blah blah blah
What that does is disarm you by distracting you with all these tantalising possibilities while he gets some, seemingly, whenever he wants with no setup, no mess, no fuss
Oh, and no need for excuses when he doen't call you, or doesn't pay attention or just plain ignores you because he knows he can just come straight back whenever he wants to.
I'd hate to sound cynical of a dude/situation I have no idea about - but I'd at least consider the possibility that he is taking advantage of you and your previous relationship while he figures out what to do next.