T.K.
Gianna is probably feeling jealous that another little girl is living with her dad full time and she only gets to see him a few times a week. I was in this exact situation 16 years ago when I married my husband - we each had a 5 year old daughter (they were actually in the same kindergarten class) and mine lived with us full time while his daughter lived with us one week, then her mom one week, etc. Each and every week, it took about 1-3 days for his daughter (and the whole family) to settle in to being a family, and just as we got back into the swing of things, she's leave for her week with her mom. It was really hard, and we saw all kinds of manipulative behaviors from her as she adjusted to the many changes in her young and confusing life (her parents' divorce, both of her parents remarrying within a year, new siblings in each family, etc...) The fact is, she was just trying to sort things out in the only way she knew how. What helped more than anything was communication (with the whole family - talk about it openly and have everyone share their feelings about what's happening in weekly family meetings. Also, be sure to give your husband and his daughter alone time together so his daughter can be reassured that she's not losing her daddy. The important thing is not to make Gianna feel wrong or bad - she's having to adjust to so much at a very young age...imagine bouncing back and forth between two households every few days. I know, even as an adult, I wouldn't want to do it, yet kids have to cope with it all the time because of decisions their parents have made. More than anything, what Gianna needs is support, love and acceptance.
As for the rest of the family, and for you especially, simply realizing that the entire family is going through something challenging together is the first step in coming together as a family. Work together, communicate openly, support and love each other (as I'm sure you do!) and things will work out beautifully. Life is constantly providing us with challenges that call us to grow and learn. Good luck to you during this time...my daughters are now 22 years old and we all made it through alive and well - ...you will too!
T.