Jeff , after a little research i have come up with this information
You can make multiple applications ..no time restrictions , of course only one at a time ! :icon_cheesygrin:
The most difficult part of a K1 is proving the relationship is real .. so if there was a second or third application for different women then it would get harder each time to prove your sincerity. Each time would give rise to more suspicion.
Your fiancee similarly will not be precluded from receiving another visa in the future. She may return home and another US citizen may apply for a new K-1 visa for her.
Both fiancées must have met in person at least once within two years prior to filing the visa petition. This requirement may be waived by the Department of Homeland Security, but only for cases with strong cultural or religious traditions which preclude such a meeting.