If you aren't at war you don't have to continue a turn split. Play whenever is best for you. If you decide to declare in the future that's when you would want to resume playing in a turn split.
Played: Pitboss 18 - Kublai Khan of Germany Somalia | Pitboss 11 - De Gaulle of Byzantium | Pitboss 8 - Churchill of Portugal | PB7 - Mao of Native America | PBEM29 Greens - Mao of Babylon