Anna, I think the regular cheap restaurant-style "instant read" thermometers--
the kind with the sleeve that fits your pocket like a pen--are best because they can be adjusted. Just put them in a cup of crushed ice and water and turn the dial to 32*.
Eventually they get very slow, hardly "instant," but they're cheap to replace.
By the way, if your husband is sneaking tastes of your pork it is probably perfect.