Before you can get away, OP, and there's no question that you need to, for your own sake and your son's, yes, see if you can go regularly to a Sure Start centre, or even a local baby/toddler group, so your son can play the way children are supposed to, without an adult clearly finding every movement of theirs wrong or irritating.
And if he doesn't have toys at home, encourage him to play with all the interesting things that are in the house - let him take safe things out of low cupboards, stack and bang saucepans, take the cushions off the sofa to make a den, make up a box of things with different textures, play with water, bake etc etc. At 18 months - with a frankly mad amount of toys, as an only grandchild - my son used to love scrunching tinfoil and playing with saucepans and and had one cupboard of Tupperware and lunchboxes etc he was allowed to empty. You can make playdough with water and flour easily, too.
But that's just an interim suggestion. You and your little boy are worth far more than this half-life. This is an abusive relationship, and the most appalling thing about your posts is how little you obviously feel you deserve, and how resigned to being mistreated you are.