I have a friend who was a single mom and now she's married. She said, "I waited so long for a partner to help me parent and now that he’s here I’m having a hard time letting him be part of the team.”
It’s a fairly common dynamic. Not because biological parents are overprotective or controlling like sometimes they are accused of but because they are used to making all the decisions. Here’s my tip. Slow down. Don’t give the kids an answer right away. Take time and include the stepparent. Yes, you'll have to work at it but it's worth it. That's how you teach your kids respect for their stepparent and then everybody wins.