Watching her give birth to our daughter. No drugs. Just natural child birth (in a hospital).
Years later, discussing childbirth with her (now) 20yo daughter (my step daughter), when asked why she did it that way for all three of her kids, she simply said it was something she wanted go go through, to feel connected to the experience of having her kids.
Awe and pride don’t even begin to explain what I felt (and still feel) for my wife.