When we accept a boundary violation once, when it happens again, we accept it, because we’ve accepted it before. It’s familiar. We know how it will go. We know we can survive it. We know that, on some level, speaking up might cause the person who crossed our boundary to walk away. So we allow them to stomp over that boundary just so they stay. Something else you may have done is tell them that the way you feel is a result of the way they’re treating you.

