Family: Try harder or sever ties?

This post is for feedback - I am tired of struggling - so many things unsaid between me and my father. He is not the man I used to know. Who is this callous man, uncaring of the emotional damage he inflicts, especially on the one person he vowed to never abandon? Being alive doesn't mean he is THERE. Speaking words, does not qualify as TALKING. Why can't he SEE?
Have I tried to talk to him? Of course. Lately - no. Why bother, when he has made it abundantly clear that he will not change, nor compromise, not even when he is breaking my heart, so I will not give him more power by admitting my hurt out loud.
Day by day I am forced to go to work like everything is ok. I know it is not, but I don't think he does. Can't he see the big elephant in the room that we just keep pretending does not exist? I cannot live like this.
Thank God for my husband- he is the one constant - the one I can depend on no matter what.
Mom & I are getting back on track -it's been a long road- but we are learning to trust one another again. I don't see that hope with my father. So sad, I was always Daddy's little girl...
My question is: when is enough enough? How do you sever ties with your blood? Your thoughts on this would be much appreciated.