I have some experience in this department. My grandmothers and father all died
young, and my grandfathers and mother remarried. My best advice is not to
force any relationship. Give it time, and allow things to happen naturally.
When my parents married, I was 17 and I didn't like my new step-sister.
However, we are now close friends. My parent just planned fun things to do as a
family, and eventually we all became a family.
Another source of stress for blended families arises when one or both spouses
fail to plan their estates and their families are unintentionally disinherited.
Even if each spouse makes a will or trust, improper titling of assets in joint
ownership or improper designation of insurance and retirement plan beneficiaries
can conflict with and will supercede language in those documents. Adult children
of blended families who otherwise lived in harmony when they were young can
quickly become embroiled in "family civil war" with each other if their
parents have failed to plan their estates properly.