People do it because it suits them. And they don't feel guilty or bad because you don't say anything or express yourself in any way.

Imagine an (exaggerated) situation where someone takes advantage of you or treats you badly. And you started crying really hard and telling this person things like "why are you doing this to me? please answer me! why are you so mean? don't you see it hurts me when you do that!".

This person would immediately be taken aback, then feel really bad and uncomfortable. It's because you overwhelmed them with strong emotions. Most people would apologize.

You are closed off. You keep these things to yourself. They can't recognize that you have feelings (and they often do anything to avoid knowing this). So they keep doing this because they think you are okay with this treatment.

There is nothing wrong with your personality, just your way of functioning. It's probably a defense mechanism you developed as a child. You need to open up, show emotions and express your desires with your words.

Are you seeing a therapist ?

I made a A LOT of assumptions here.