16 year old cousin is dating a 26 year old
Over here I wouldn't personally see the problem (here, she would be of age to do as she pleases), but I know others would.
Only if this was true
it seems that he really cares for her.
And he proved his character to be good and honest.
As it is, if it is against the law there for them to have sex at her age I would be slightly more worried and remind him of this fact. A lot. If he is honestly willing to wait for that then he must really care. (And possibly is a saint - it's hard to imagine) Thing is - would they tell you honestly
anyway if they had already had sex or not?