I don’t think I would be offended but no doubt I would be hurt. But knowing what I know of people and divorces the first two words that pop into my head are shame and guilt. I don’t know your dad (obviously) but these are the feelings that dads and moms often have with regard to children when divorcing. I guess if I were you and I really wanted contact with the man, then I would continue to send emails and call occasionally as well to let him know that you love him, have no ill feelings towards him and still want his presence in your life and your family as well. I would do that whether I received a response or not. I think eventually he will realize that you need him and he needs you and he will get over whatever is keeping him away.