You can stop him stealing from you by breaking up with him. This has gone way too far.

If you tell someone that you don’t want to be disrespected and they keep disrespecting you, it’s time to reflect ob what they’re adding to your life that makes up for that sort of behaviour. I know it‘s not easy to act on something like this but at least be aware that this isn’t normal behaviour in an adult relationship. You deserve to be treated better.