Pstone:
Even if he met his mistress being an impersonator, it doesn't go into the logline unless it contributes to event-character-goal dynamics. Which it doesn't, so I'm substituting it for an adulterer for now...
also,
You said "his learning they are pregnant" isn't the INCITING EVENT........that the event happened before.
WHAT EXACTLY IS IT since it is a MANDATORY part of the logline
If you want me to trim your version, here you go:
"After impregnating both his wife and mistress, an adulterer must keep it a secret or risk winding up a vagrant"
It's obvious that this action "keeping their pregnancies a secret" cannot sustain a feature length plot (as pointed out by Jessie...thanks J)
Also it's a selfish goal--to keep a secret, to save his a** from being on the line
I strongly suggest you to HAVE A BETTER GOAL
Because this premise of living two lives, is worth investing your time into...