R.K.
It doesn't matter who belongs to who, first of all. They are children and they have been through a traumatizing realization that they have no control over...Divorce/Break up. Believe it or not they blame themselves, but when you came along...you became the dump truck. Try to spend some quality time as a whole family. Get the older one's to help with the younger one's. For example, say hey (9 yo girl)would you mind holding your (sibling) while I get a diaper? Let them know they are a part of your family, this helps them to feel they belong instead of wondering where they belong. It doesn't matter what mom's home is like you let them know this is how dad's house is and we all must do our part. I know it's not easy but try to put yourself in thier shoes-you wouldn't like it but you can control it. i have a family room gated off with some legos and dolls, I put kid flicks on and the kids are content. The older ones like to color and circle things they want from catalogs (junk mail catalogs). They dream and keep busy. 3 year olds also love to look at catalogs. Discipline for children under 5 should be time out older than 5 should have privileges taken away for a day or two. good luck!