can children be jealous of their father's relationship with their step-mother

Children that young can at times be very jealous of things if attention is being adverted from them. Not only that the child could be acting out, because the little girl wants her mom and dad back together. Again she don't understand why mommy and daddy broke up in the first place. The dad needs to explain to his daughter that there are certain reasons why mommy and daddy can't be together anymore, and that it is ok for daddy to see other woman. But both of them need to get after the little girl when she starts pulling this stuff so that way she starts learning that being mean or breaking things is not the way to get good attention from dad.