You can't insist S tell his Dad. Just hug that little honey and encourage him to do so. If he won't, then don't push. Should you tell your H? Maybe, but at a quiet, calm time if you do and not in the heat of the moment.
Me 45, H 46, S 23, M 26, Together 30, Bomb 6-2-08, S 6-19-08; H left 12-29-08. H home 12-09, Still MLC in 2012! Me- I have my big girl panties on. Bring it.