Louise,

I can see why it is confusing for you for he is sending mixed signals.  Sex then talk of future then offer to bring tablets then…

This just highlights how inconsistent and confused he is.  I would find it hard to deal with anyone like that much less a romantic partner.

This is classic push-pull.  Where he pushes you away then reels you back in with words and deeds and then he gets scared again and pushes you away…   I think this is what those with Anxious Attachment style people do (you can Google that).  His behavior shows that he does not want to let go and he cannot be close or attached.

You cannot leave him because you are not yet committed to your own *full* and healthy happiness and therefore not ready to leave him.

Make sense?
Mark