Satchel explains it in today’s Get Fuzzy.
What you should be saying in that case is “You can have your cake then eat it” which makes it clear the having occurred before the eating.
If Archie says “I want to marry Betty and Veronica” the assumption is going to be that he’s thinking about polygamy not serial marriage. He should have made his intentions clear by saying “I want to marry Betty then Veronica.”