i'd say it's likely yal both ate bad food... of course, in his sleep he could heard you puking, alot of people gag, or even puke when they hear other people doing it, just like yawning... you could both be coming down with the flu/other virus.... there are numerous reasons why you'd both be puking... and i don't find it completely impossible that w/e the culprit is that it took roughly the same time to make the two of you naseaus... however if you didn't eat the same thing, or didn't come into contact with each other or the same people (i.e. you didn't give each other w/e illness it could be or you both weren't around whoever gave it to you, i.e. only one ofyou was around a sick person) then i'd say he probably heard you puking, then he needed to...

any other symptoms?