How to develop fortitude?

Specifically when someone you love or whose opinion matters to you greatly attacks your way of life, your beliefs, or even on a smaller scale just makes you feel ignored, pushed around, etc. I find I quickly lose confidence in my "inner voice" when my loved ones, particularly family, do this. Generally when a stranger does this to me it's easier to let go. Does anyone have a useful visual metaphor or story around this? I try to see myself as a rock and their words like arrows pinging off me but it doesn't work.