A little heartbroken and lost

Teen has been stealing from me. He has gone through my cupboards and drawers in my bedroom and taken items from there. He goes through the cupboards in the kitchen and helps himself to whatever he wants without checking that it is ok to have (there has been a number of occasions where he has eaten food set aside for school lunches). I have one shelf in the kitchen that I reserve for myself, it has my healthy snacks, my protein powder and, on the rare occasion there is enough money in the house, it is where I put my chocolate.

Trust in this house is assumed. Basic respect of space and property is expected. Unfortunately Teen seems to have completely bypassed the lessons on trust and respect. Nothing is safe from his prying hands and eyes. If he wants something, he takes it. He has lost all my tools by not returning them after use, destroyed my garden fork because he had the shits, destroyed an outdoor broom that belongs to the owners of the house, put dents in the walls.

The current last straw was when I went to my cupboard last night to enjoy some chocolate that my brother had bought me as a gift. It was gone. I immediately confronted Teen, who said he took some. I pointed out that the whole block was gone, so where was the rest of it? He got it from his school bag. Less than half a block. I was close to tears, I had been looking forward to this treat all day. I yelled at him, saying that it was a gift from my brother, that Teen invades every space in this house, so why could I not have just this one shelf that he does not touch? He had nothing for me, did not seem phased by how upset I was.

I feel like I have nothing left for him. Trust and respect is so important to me and I feel that it is beyond me to generate any more forgiveness for this person who cares so little for other people's things.

I am devastated. I do not know what to do. I do not want to be around him. I do not want him near me. I want to turn my back on him. I am so lost.

I feel like a failure as a parent.