Smart Nora is designed to be adjusted for the individual's needs. In a situation with two snoring partners, the sensitivity for each device can be modified accordingly so that each is activated when needed. While we haven't tested extensively in sleep environments with two snorers, Smart Nora could be tuned to respond to more than one snorer. The chances of your partner's snores setting off your Smart Nora would depend on a few factors, including volume and their position relative to the Pebble's microphone.
There will be some instances where a partner's snore may set off the other person's pillow insert, but the movement of the insert is so gentle as to not wake you. If both of you are asleep, these occasional double inflations shouldn't disturb your sleep.