Family Law Attorney Alexandra Haile answers how much say an ex gets to have on your custodial time with your child.  The short and simple answer is your ex doesn't get to control the time you spend with your child.  If you have a child custody order in place it likely says that each parent has the right to make the day-to-day decisions.  For example what the child has for dinner.
However, a common issue is who the child can be around. Usually, that is a problem with exes starting dating new people.  But, unless your custody order specifically says your child can't be around them you are free to introduce them.
When it comes to the custodial time you are usually required to inform your ex of when you will be on vacation, who will be going with you, and travel information.  But, it doesn't allow the other parent to say yes or no to the vacation.