@Glostar: That is very strange. Are you certain that your Watch6 was not connected to your husbands phone, as this is the only means by which an alarm would sound on your watch? To double check, please ask your husband to head to the Clock app > Alarm tab, then check the active alarms to see if anything corresponds with the alarm you heard. He should also head to Settings > Connections > Bluetooth, and check the connected devices section to see if the Watch6 is listed here. On the watch itself, select the 'Alarm' app, and explore your current settings from here.
