let him have respect for both. don’t try to create any hatred in him. they may have done wrong. why you want to make same mistake. think what will happen to the child. it will hurt him emotionally. why do you want to do that. instead try to be a good father. you have moved on in your life. let him have a mother atleast by his side as she chose to be single for him. why do you want him to make any judgement. let him be happy. he can understand if she is cruel towards him. do you think if you tell all bad about mother in one fine day he will change his attitude and start loving you.