Unconditional Love and Boundaries

I’ve just had a 20-minute coaching session about my strong desire (and current apparent inability) to set boundaries with a friend of mine. The coach pointed out that I have not yet forgiven my friend for several things she has done.  This is very true!  The coach also said that we are best able to set boundaries from a place of unconditional love.  I can see that this is true too.  If I felt unconditional love for my friend right now, I’d find it much easier to set boundaries with her because I could do it “knowing” that I was coming from a truly loving place, so I wouldn’t feel that I was being harsh or uncharitable by setting the boundary.  As it is though, my ‘unforgiving’ model is:

C – friend’s behavior
T – she’s a total s**t
F – disgust
A – stew over what she did; say things to myself like “I cannot believe she’d do that!”; in my dealings with her, I try to be as nice and polite as possible while secretly seething with anger.
R – I use cognitive bias to gather more evidence in support of my belief she’s a total s**t

I know that I could think different thoughts about her like, “Everyone behaves badly sometimes and they still deserve love” to produce different feelings.  I think I am quite happy to think “She’s a total s**t”.  I don’t necessarily want to change that belief!  I don’t necessarily want a friend in my life who is capable of behaving in that way to me.

But it seems that we can’t set boundaries in the best way unless/until we’re coming from a place of unconditional love.  So does that mean that for as long as my thoughts about her are negative, unforgiving ones, I should remain friends with her and not take any steps to protect myself from her constant sending of messages/letters in which she nastily character-assassinates my other close friends?  Surely not!  Help!