If the way you are treated makes you feel awful and used, then that's how you feel. No one here has a right to say you're "just" being "paranoid" because those feelings belong to you.

So, either address this issue with your SO, or end it, ASAP.

Sorry you're feeling this way. If you can financially sustain yourself, then don't settle for someone who is taking advantage of you. Cut the cord. Move forward.