The examples I gave were times when I have made last minute decisions to go out and my kids were in bed already
Single parent a decade--never done that. My S can always come running to me, for example, if he has nightmares or there's a storm. Do last-minute late night plans come up often? I sometimes leave before they're up for a breakfast run. In that case I leave them a note. That could work here? I like leaving little notes to my kids. I add a "To S, <3 Dada", sometimes I embellish it with rays around it.