((((Tremor))))))

You are allowed to feel any way you do. Of COURSE you loved him. He was your father. It is difficult to take away loving someone, even if they abused you.
You could look at it not so much that you're grieving your specific father, but also that you're grieving having a father figure at all. You're grieving the lost opportunities as a child, as an adult with a father. You're grieving the possibility that he could change and be the father you always wished for. Even if logically you knew that may not have happened, it would be extremely rare if you didn't hope for that in your heart. knowing the contact is over makes that possibility much less likely.

It sounds like amazing progress to find out that your alter is there because she feels you need her. I take it as proof that she is there to protect you, even if she doesn't know the best way to do this. I had an alter that was so angry at people, and when she took over I'd say and do things that made people really not want to be around me. I was so upset with her for pushing people away. Finally I realized that she in her own way was really trying to protect us from being hurt, by hurting other people first. I was able to genuinely thank her for that and eventually she has become a very dear part of me. Many times it feels like alters just need some recognition, and they settle down a little and are more easy to work with.
I hope writing or talking to her can help you out with this! You are an amazing person, for sure!!
All my best,
IJ