Why isn't my new husband treating my eight year boy the way I want him to?

My son is from my first marriage and at the beginning my husband was trying to convince me to bring my son to live with us. I was reluctant but I did it because I missed my son. However, seems like he is not exactly what I envisioned a stepdad to be. He is not abusive to him but he doesn't do much for him like he is my only responsibility which doesn't fly with me. What is your opinion on stepdad's treatment and if it's commmon.