I love my husband But....

Grrrr my husband can drive me nuts! He is step dad and only dad to my son and has been for the last 3 almost 4 years. He has never been a parent before and he is to hard on my son and even though I know he loves him and my son loves him back, he just doesn't understand parenting. He wont take parenting classes and when I suggest that he take them he throws it at me that I am not the best mom and I need to take them too. He infuriates me so bad. I can never have a conversation with him about things he may be doing wrong or tell him how I feel without him taking it as a personal attack! Its ridiculous! I'm tired of people trying to make me the other parent. I AM HIS MOM! I GAVE BIRTH TO HIM! BACK OFF!!!!