I personally would go with the third option. I'm in college too, and up until recently didn't have diapers as it wasn't really feasible. That being said, I'm going to try and wear while my roomate is out of town and no possibility of him finding out. Because of how close our friend groups are and how early in the year it is, I'm not (and wouldn't recommended) spilling your guts to your roomate, or coming up with an excuse like bedwetting because it might have unintended consequences. I'd just say be careful about it, and if the situation does present itself, either play it off and pretend it didn't happen, or if your roomate confronts you about it then you can evaluate options depending on how close you and your roomate are- if he's understanding/accepting of most things (and confronts you about it), maybe spill it. If he's typically close-minded, try to pretend it didn't happen and tell him he doesn't need to concern himself with it.