not sure, but if you don't want them to know you don't like their posts, you can hide their posts. you won't see them and the person will not know.
I'm sure i was unfriended and it did hurt... i found out because suddenly this person's posts no longer showed up on my profile and when i checked this person was no longer on my friend list either. wish she woulda had the decency to have told me which posts had offended her or whatever had upset her.
If you think the person might notice the unfriending, you can also block them. That way you basically are invisible to the person you unfriended. I have some people that I just hid their posts, and others I had to unfriend, and I always take the extra step to block as well. Life is too short to have to deal with some people stirring the pot, kwim?