How do you set boundaries with someone who always makes you feel guilty for having them?

You finally say the thing, draw the line, ask for what you need — and somehow you end up being the one who has to apologize.

Boundaries are supposed to protect you, but with certain people they just become the next thing to feel bad about.

Have you ever tried to set a boundary only to have it used against you — and did you ever find a way to hold it anyway?