Jamie always has the best advice, doesn't she?
I was actually very pleased to find this thread, because I have two daughters ages 8 and 13. My 13 year old can be very manipulative and selfish. My 8 year old has full grasp that she is the center of the universe. Actually the younger one is better. The reason I find this thread so interesting is that it made me realize that in my relationships with others (my boyfriend of 8 months) that parenting is tough. It could easily destroy a relationship of good potential.
So now I put myself in your husband's shoes, because I am that person. If my signifigant other came to me, complaining of petty problems, I may roll my eyes. But if I knew that it drained him emotionally, well then he would have my attention. I agree that you are not going to get far being the evil stepmom, and making extra rules. But your husband should realize that he is being walked on.
Two months ago my 13 year old pulled the garbage your stepchildren did. I walked into her room, and gave her a list. I said "You picked the wrong day to piss me off Missy..." Her punishment was she pays her cellphone bill. Any more attitude, and she spends the days I work with her overbearing grandfather. She has chores on a daily basis. Laying down the law and standing up was the best thing I did. She cried, she apologized, and ultimately, she changed.
A kick in the ass (hypothetically speaking) isn't always the worst thing. It reminds them that they are NOT in control. Coddling them will only encourage it.
JUST IMHO