With the divorce rate so high today, it is not uncommon for a parent to marry and have children from a previous relationship. Step parenting is a little more complicated than parenting your own biological kids. There are other parents involved, but building a successful blended family is possible with a little work and effort.
As a step parent, there is no biological or blood tie between you and the child. You also have to deal with any interactions or visits from the biological parent who does not live with the child. For example, you could marry a woman who has two children from a previous marriage. She may have joint custody, with the ex-husband having custody on the weekends. What is your role as the stepfather who lives with the children?
The most important thing to consider is to present a united front with the mother, who is also your wife. Consistency is important when parenting, especially to young children. Creating a stable environment with established boundaries will provide comfort to the child. The child will know what to expect and hopefully will abide by these boundaries. You will probably become the main male role model in the house, as you are there every day and the children will see you interacting with their mother. They will seek you out for attention and guidance. Constant positive interaction between you and the children will create a stable family relationship.
If the relationship with the ex-husband is amicable, then you as the stepfather should also try to establish a similar type of relationship with him. That would make the custody transitions easier and less stressful for the whole family and allow for an open path of communication. When he comes to pick up the kids for the weekend, you want the children to see everyone getting along.
For older children, your role may be a little different. Older children, especially those who are teenagers, are more aware and independent. You as a stepfather may play more the role of a friend or trusted adult, similar to that of a teacher. You do not want to replace their biological father in their eyes, but you need to make sure that they see you as a person of authority in the household.
As with any relationship, you need to constantly work at maintaining that relationship. The same holds true with step parenting. As the children grow older and mature, you may need to adjust your parenting methods. Communication with your spouse is key to a successful blended family.