As the married partner in a V-I think it's rude.
I always check with my partners (both of them) before I make date plans-because we have to schedule around work and kids.
HOWEVER, we also ALwAYS solidify a plan together, not just leave it out waiting to the last minute.
Now, it may come up that one of us has free time at hte last minute-and that is fine. But, if it's a romantic date we're planning-that sort of "well if it turns out I'm not busy" attitude would result in that person being left on their own while the others went and did something else.
"Love As Thou Wilt"