I thought it might be a good idea to take my ten year old to visit his prospective stepmother and stepbrother.
It took some courage on his part to come and to meet people he had never met before, I think.
But in the event the "Wicked Stepmother" gets an unconditional seal of approval ("Go on, Dad, what are you waiting for - marry her!") and even the small stepbrother can be coped with ("Was I really like that to my brother?" - "Yes, you jolly well were!")