NC here. It's just easier.
My DS is 6 months old. DH, DS, and my parents went on holiday recently.
At one point, after a meal, DS was covered in food and needed a wash. My DF was about to shower and offered to take DS in with him (so his DGS).
I said fine. My DM stood outside cubicle with towel, while my DF and DS showered. Both enjoyed it.
Afterwards we were putting on a clean nappy and DS discovers his penis for the first time. This completely freaked out my DH who has now decided he's really uncomfy with DS showering with my dad, and has started to notice things when my dad looks after DS. For example, when changing his nappy, my DF waved the wipe around in a 'feather duster' type way, around DS's nappy area. I took this as my DF just having fun with his grandchild; but it unnerved DH.
Of course, if something makes DH uncomfy we won't do it. We try our best to show a united front, especially in parenting. Solidarity and all that. So no big deal, we've said it's no longer appropriate at this stage of development.
But what do you think? Is DH overreacting, or would it freak you out?
(FWIW I think part of this has to do with my backstory. In brief this is as follows: my DSis has eating disorder, which DH has commented often occurs following sexual abuse. We were raised in a strictly religious yet hippy-esque fashion which meant we were smacked/grounded etc, but DM and DF also walked around naked/took baths with us until we were pubescent. VERY different from DH's upbringing. I was NEVER sexually abused though.)