Blended families exist in many forms. They are by their very definition a family by choice. Parents who have children from past relationships choosing not just marriage for themselves but to become a new family with their children.
Blended families are notorious for their unique problems but they don't have to stay mired in the history that preceded the wedding. While there are always obstacles to be considered, it is possible to use those bumps to bring the family closer together instead of building walls.
Families that have thoughtfully expressed their needs to each other, shared their feelings with respect and sought ideas for deepening relationships often find their blended families to be strong and able to withstand any hardship.
Read some popular articles:
Surviving Holidays as a Blended Family
Being Grandparents in a Blended Family