I would think that if she has only been to your house 3-4 times in a year she is using the room more like storage than anything. So, why not switch rooms and have a small room be her storage room and let the little kids who need room to play have the large room. Tell your dh that the rooms can always be switched back, if necessary, if she ends up moving back. But I think it is silly to have that large space empty and have small spaces cramped!

Why even tell her the new room arrangement? Chances are that she wont be around for months, and by the time she is you will be able to point out that the rooms were switched months ago because of her not being at your house ever! How can she argue that?

Has the 18yr old made any plans for college? That should be a real focus. That may drive housing.

Have you asked your husband what he thinks about the situation? When you bring up the concern about your children living in small rooms what does he think WOULD be an appropriate resolution for your situation? Let him know it is not about his daughter, but it IS about your children. It is obvious he is defensive about his daughter from the other marriage... If it is just about your children having small rooms then that needs to be addressed without brining up the other daughter. Once you bring her into it he will automatically get defensive. I understand you are feeling like your children are suffering because of his other daughter but try to remember that your husband sees all the children as equally HIS children. Have you thought of asking him if you all (the SD, you and him) can sit down and talk about it together? Maybe including her in the conversation may put him at ease about making a decision. As to you....no you are not wrong, your feelings are valid, I think maybe a different approach may be more productive though. Good luck

Thanks for the advice. No, she is 18 and still a freshman in high school. We will be thankful if she graduates high school. She has no plans for the future, except to keep doing exactly what she wants and allow her father and grandparents continue to pay her way.
I'm concerned this is the reason why my husband does not want to give her room up. It looks like we may be supporting her for a long time to come. I feel very uncomfortable with this idea. I feel completely helpless in this whole situation. I just don't want the other kids to suffer because of her poor choices.

Have you considered just asking her to trade rooms to let one of the other kids have a turn having the big room?

I think the problem here is turning rooms into symbols of merit, love, and favor. What would happen if you approached it simply as a space issue, and talked the same way as if everyone got along beautifully and there were no problems? She may surprise you.

"Petunia," says Dad, "We need your help on something. Cuthbert is really outgrowing that little sewing room. Would you consider letting him have a turn with the big bedroom for a while? It would be a big help. You would? Great! And you know what -- why don't you pick out some new wallpaper and bedding for your new space."

I know that is kinda "storybook," but you get the idea.

Notice especially what is NOT in that script:
- who deserves what
- comments about her or her mother's behavior
- who lives where how often
- how much sense this arrangement makes

In other words, rather than telling her that this way is the only logical and fair way, and if she doesn't comply, she's being unreasonable, let HER be the gracious one, giving rather than giving in.

Good luck!