There is not much you can do. Your father, even being mean about it all has his point that he is in fact correct about how he "claimed more right to my children than my husband" He is a blood relative and your second husband is not.
This situation sounds a rather difficult one, and there isn't a quick and easy answer.
For now, best stay away from contact with your dad, even though that will be painful for you at first and maybe later. Perhaps in time, your dad will come to realise that your husband is the gem that you already know he is. Don't put him through any more pain than necessary, or he may decide that he's had enough and make the situation worse.
Good luck, whichever way it goes.
Your dad sounds verbally abusive, belittling you in front of your children. Tell him that the things he says make you not want to see him anymore. Just make him aware of how you feel, and if he really cares, he'll change his behavior.