Let's look at this from the girls' perspective for a second. Remember, they are just little girls. You may all have gotten along great before, but along comes a baby, and everything changes. Now you're not just this nice woman who lives with Dad, you're the mother of a little bundle who takes Dad further away from them. They'd probably feel jealous if they had a new sibling in an intact household; a stepsibling or half-sibling is just another reminder of their separated, segmented lives, and kids in those situations tend to hang on to whatever is theirs.
Given time, plenty of attention, and -- this is key -- consistency in their schedule and discipline, they girls will be fine. The problem seems to be your husband, who (in fairness to him) is probably reluctant to be the bad cop; we all know how much easier it is to give in to bad behavior than it is to step up. You need to help him see that giving in is not a good way to show his daughters he still loves them. In fact, letting them get away with things they didn't before the baby arrived gives them the message that he cares less. The girls don't see this, but they feel it. Kids crave security and familiarity. They push against parents to test where the limits are, and if you remove the limits, they go a little nuts.
Try to explain to your husband that he can find better ways to show his love. For instance, he can take them out for cupcakes, maybe with the new baby in a stroller, which is a way to give them a treat while also showing them that the baby is part of their lives too. He can mix that up with time he spends just with them. Persuade him, when the girls are at your house, to handle their bedtime while you deal with the baby. These girls need to know that their dad still loves them -- but they also need to know their dad is still very much in charge. --Denise Schipani
Originally published in American Baby magazine, February 2008..Updated 2009