Spouse withholding child's passport

We’re in the middle of negotiating a separation and my spouse agreed that I could take our daughter on a vacation this summer for three weeks. It’s partly a big family gathering but the two of us planned to travel a bit and were going to stay two days in Canada. Everything has been booked for two month and my daughter and I have shared lots of time discussing what we are going to do. Now my wife wants to withhold our daughter’s passport because “she doesn’t feel comfortable” with me taking our daughter out of the country. It’s Canada! Barely qualifies as another country. The cost of changing everything last minute even for just a couple days, is pretty significant as now I’ll have to pay last minute rates in peak season.
Can she really get away with this flagrant manipulation? And is there anything I can do given there’s not a lot of time to fix it?

I would consider filing an action for child custody and including a motion for temporary restraining order that she hand over the passport. Whether that type of motion would be effective would depend on the jurisdiction you are in, but it’s the only mechanism I can think of that would obtain results for you in a timely manner.