He has never denied to have some fun. I think he took things even more seriously when he was young hence the no sex rule. Then he probably relaxed a little and started to enjoy life more outside of the grid.
As for him not bragging I think it’s more to prevent some potential “fuck boy” comments than the whole my private life is private. He literally shows everything else, family included. He just wants to keep his hook ups in the down low which is fair. No one needs to know how many girls he has slept with even if we are curious