Q: My husband and I have been married 10 years. We met two years after his divorce. I have no children and he has three adult daughters. The oldest two are open and respectful of me, but the youngest simply acts nasty and makes inappropriate comments when visiting our home. How do I deal with a bonus daughter who seems to dislike me, for reasons no one can determine? I don't want this to come between me and my husband.

A: Speculating, the most common issue I see is that you and your husband didn't properly prepare his children for your remarriage. Thinking that his kids were adults and you could reason with them, not enough time was spent preparing them for the changes ahead.

Youngest children are often used to getting their way and they act out, no matter their age. If the youngest is acting rude and disrespectful, I would venture to think she has been allowed to act like that during other ventures.

It's difficult to establish boundaries after 10 years. You should have agreed upon house rules and how you will interact with each other's children prior to moving in together. There is an exercise on the bonusfamilies website, www.bonusfamilies.com, called the Before exercise. It asks parents and bonus parents to consider the relationship they want to have with each other's children and put that in place prior to moving in.

So, what to do now?

The ex-etiquette rule of thumb in these cases is, "you control your extended family, your husband controls his." Therefore, once house rules are established, if your husband's daughter is being disrespectful, he's the one to call her on it. You stay out of it.

It's tough to backtrack once a precedent has been established. Since your bonus daughter has been allowed to be disrespectful, if asked to stop, she might pull out all the stops trying to regain control. That's when your husband must stick to his guns. If his daughter does not change her behavior, he may have to find ways to see her one-on-one or possibly suggest therapy to explore the things that are contributing to the behavior, but to allow you to be disrespected in own your home will eventually undermine your relationship with your husband — and the outcome will not be positive.

Finally, I cannot stress how important it is to properly prepare children before moving in together or remarriage. No matter their age, they will want to know how things will change and how this new union will affect them.

E-mail Jann Blackstone at dr.jannexetiquette.com.