To begin with, if custody and access to your child has already been determined by a court on a temporary or final basis, (i.e. there is a Court Order in place), then you may have to stick to the schedule for the holidays.
However, if you are newly separated from your ex and there is no Order or agreement yet, then best solution is simply negotiation: You should sit down with your ex and reach agreement over the details of a holiday schedule that works for both of you.
Depending on your unique circumstances, this may include some negotiated blocks of time that you all spend together, or it may refer to specified holiday events (such as your child’s school concert or play) where you and your ex can both attend. Cooperation and civility is always the optimal solution, since it serves the best interests of your child.