I totally get this. My bio-father sexually abused me and my sisters. I have no love for the man. He's been dead for 40 years. My sisters will sometimes post something about him on his birthday - I feel nothing!! I will never understand why they give him a thought at all. My father, the man I called dad was my adoptive father. He never hurt me and was always there for me. I did forgive my bio-father after he died. I went to his grave and screamed at him, I vomited out all the anger I had and I let it go. I was then able to move on. I have wondered this myself. I was hurt deeply by my bio-father and I have no feeling for him what so ever and yet my son has hurt me deeply too and yet I still love him. I do love him but I do not like him nor do I trust him. He is not someone I would seek out to have a relationship with. Why the difference? I don't' know that I will ever know or understand. What I do know is that when it comes to my son I take it one day or one incident at a time. There could come a day that he and I have no communication at all and if that were to happen, I would be okay with it.