We do not seek permission but we discuss. We discuss our finances in general, how much we have in retirement, how much in the grandchildren's education plans, etc. So of course we discuss big purchases.
We do take some separate vacations. He golfs and has a pretty hefty country club bill in addition to traveling to play golf. I like to do vacations with my friends. Since we have dogs that need to be looked after, we do run it by each other to make sure we know what the other is doing. To me, that's fairly typical married behavior.
We take a large international vacation together annually. We rotate every other year in selecting the destination/activities.
Although this year's (his choice) was so awful I may have to rethink how we do this one.