I am a regular poster - but I've name changed as DH often browses MN.
DH had DS (10mo) on his lap, and DS yanks his arm hair, so DH slapped him on the arm. Not hard, but DS immediately started crying and I snatched him away from DS and gave him a cuddle.
It was all forgotten by DS ten minutes later, but hours later I haven't.
I cannot believe DH hit DS, yes he was being annoying but he is a BABY FFS!
I told him that if he ever did anything like that again that it would be over for us.
Just needed to off load, tbh.