My new husband has unrealistic expectations of my teenage son

I raised my 2 children alone for the past 11 years. I recently got re-married. My new husband has some great qualities, but he has never had any of his own children and never been married. I want him to let me continue to do all or most of the disciplining, grounding, lecturing, following up when they don't do chores etc. He thinks that because he lived with a women who had kids, for about 4 years, he has some understanding of what the expectations should be. Fact...white trash women with white trash kids (sorry). I just want peace in my house. I want to continue to make the major decisions about behavior and if I need him to step in, I will ask for his help. I want the kids to like him so I want him to back off as far as disiplining goes. By the way, the worst things they do are forget to empty all the trash or miss 1 homework assignment. These are REALLY good kids. When my 17 year old son gets disrespectful and my husband steps in, it makes it worse. HELP!