It depends on what type of hydrangea it is. In your zone, I am assuming it was either an arborescens like Annabelle or a paniculata - both are very hardy and produce white flowers. And both bloom on new growth. These can also tolerate quite heavy pruning, but generally that is best left until early spring. However, given their hardiness and the fact that your shrub was well-established, chances are very good that it will re-emerge later in the spring.

And keep those pruners away from your boyfriend unless he knows what he's doing :-))!!