There are actually watches/bands that will give a minor shock as an alarm. Sounds crazy but unless it jump to the wife (hope it wouldn't be that strong...) it shouldn't wake anyone. Novel idea if nothing else.
Interesting. Looks like "Pavlok" is the main brand. If OP buys their more expensive one OP could use it to silently wake up AND train himself to get out of bed super gently by shocking himself anytime he disturbs his wife!