Perhaps your stepbrother is getting married and his bride has asked your children to be flower girls in their wedding. You love your daughters and know they would glow in the spotlight, dressed as little princesses haphazardly throwing roses down the aisle. But you suspect that dormant old rage may reactivate. To honor this occasion and please your kids you think maybe the time for reconciliation is at hand.
But you feel this stepbrother, who entered your life when Mom divorced Dad and married again and blew apart your warm family nest, does not deserve your support. You are still angry with him for ruining your family, draining away your parent's love, even though you know blaming him is easier than blaming Mom or your stepdad. On top of this should you hold the next generation hostage by not allowing your children to be in his wedding?
What if you turn your stepbrother down? These are some bridges to cross with such shaky infrastructure that you could surely fall into a chasm taking your own kids along with you. 
 Perhaps you need to seek resolution with that step brother before the summer  wedding. Checkout my book Mom Loves You Best http://www.amazon.com/Mom-Loves-You-Best-Relationships/dp/0882823213