Relationships

A friend of mine posted on Facebook, "relationships are like glass, sometimes it's better to leave it broken than to hurt yourself putting it back together". Through my almost 30 years of existence, I have made friends that I've kept and had to let go of some. Most cases it had nothing to do with the relationship breaking; it was more like a growing apart.
Recently, I had a really close relationship of mine come to a head, so to speak. I've tried numerous times in the past to hold it together, to be the one that bends backward. I got to a point that I was very angry at having to reply the same way over and over. I got tired to trying to pacify this person that has an almost insatiable mind full of blame and guilt. Is there a point even in doing so? Why should I continue to suffer at the hands of insecurity?
I have a happy life. I live where I want. My friends are there for me. My husband is there for me. Everyone loves me for me save this one.
Many thoughts course through my brain, especially while I'm asleep. The dreams keep coming. I wake up feeling guilty sometimes. What's my next move?