I can’t ask this from my rabbi. My father molested me twice as a kid. I am in normal contact with him but it kills me to be civil. Do I have an obligation of kibbud av? He did the unthinkable after all.
I am sorry to hear about this terrible situation.
There is no obligation to honor a parent who molested you. A person is not required to give of his money for the purpose of honoring parents. If this is true for his money, it is all the more true for his entire dignity or even his life, which can be terribly affected by a “coerced” relationship of honor.
Moreover, a parent who so damages his child is not worthy of respect (see sources).
This is not to say that your relationship with him cannot change over time.
Best wishes and good luck.
The Talmud records cases of abusive parents, and mentions that in spite of the parents’ behavior (parents who used to shame their children, and parents who used to damage them financially), the Sages would continue to honor their parents. This is also mentioned in Shulchan Aruch (Yoreh De’ah 240:3, 8).
However, it is very difficult, and almost impossible, to give due honor to abusive parents, and certainly for a parent who actually molests his child. For the sake of the children, abusive parents must be distanced from their children, and distancing them would also solve the problem of honoring them.
Indeed, several authorities advise that in circumstances where honoring parents is difficult/impossible, one should simply move out of the neighborhood, and try to avoid confrontation (for instance, see Aruch Hashulchan, 240:33, concerning a drunk parent).
But as noted in the answer, a child does not need to spend his own money for honoring his parents, and this is the more true of his basic dignity.
Furthermore, If parents are wicked (resha’im), authorities (Rambam and Tur) dispute whether or not there remains an obligation to honor them (see also Aruch Hashulchan, loc. cit.). If the wicked behavior of parents was directed at the child himself, there is all the more so no obligation of Kavod.
This is not to say that people and relationships cannot change – but this depends on you and your feelings before anything else.