Getting Him Involved with Childrearing
As the children grow, you need to be vocal about your desire to include your partner in the childrearing, or else he may continue to assume that it's a task best left to you.
It's not only mom who benefits when dad pitches in to help with the kids. Studies show that children whose fathers are involved in their lives in a meaningful way grow up smarter, healthier, and more socially adaptable. A man helping around the house isn't necessarily a modern or feminist issue; even families that hold traditional, conservative values generally agree that a father needs to exhibit his nurturing, care-taking side with his family.
Strategies to Get Him Involved
Let him know you want him to be more involved, and specify the way you want him to accomplish this. Don't nag or accuse him, just let him know it would be better for everyone involved if he could pitch in a bit more. If you need a hand with specific everyday tasks, try and be as detailed as possible. For example, if you'd like him to change the baby's diaper anytime you're busy with dinner (whether preparing it or feeding another child), say so specifically. That way he'll know when his turn has come up, and won't have any legitimate reason to shirk.