J.P.
My husband and I have the his and mine situation. Our kids are a bit younger but we had the same blantent disrespect problem. I became full time child care for his daughter and she would mouth off, take my things, whatever she saw fit (her house, her rules who was I to change that!?!?!?). My husband had a considerable amount of guilt due to his ex-wifes lack of involvement and would come home daily and spoil and over indulge her because she was upset with me. My husband completely misunderstood my intentions and it caused a great amount of difficulty between us. It took a while but we finally came together. What we did (with the assistance of some church counceling) was create house rules for all those who lived there, that were initially enforced by the biological parent. There was a set of rule and a cooridinating set of consequences. WHen one was broken, the child was told that their parent would be enforcing the punishment when they got home. It worked wonders, it removed me from the conflict and caused my husband to realize that there were issues he needed to address with his daughter. IT brought us a lot closer as a family and now any adult in the house can easily enforce rules and consequences. Keep your chin up. You're doing what you think is best for everyone in your house. You're doing the right thing. Hang in there, your husband will come around.