hold strong to your values as a mother and let no one including your husband stray you otherwise. you are your children's biggest advocate on this planet.
i don't believe in "changing" people. seems odd he was so accepting of your ways early on but has now fallen back. maybe it's because things are tougher now with three children.
his abusive past isn't helping. although that makes some people commit to never doing that to their children, other people (like maybe your husband) simply do what they know when it comes to parenting.
maybe it's my personality, but i like to think it's my committment to being a mom, but i would not allow ANYONE to treat my children in abusive ways. i would stand firm to your morals as a mother. any arguments about the way you parent should take place away from the children.