Many parents decide to have new relationships after divorce which will affect the childrena as well. Keep in mind a few things:
Keep all parents involved.
Tell your children that your new partnew will not be a rplacement parent, but another person to support them.
Establish the role of step-parent as more of a friend rather than a disciplinarian and let the biological parent handle the discipline.
Be aware of favoritism and dont overcopensate by giving more attention to the step children over your own children.
Spend time everyday with your child.