I had pups born here from 2 different moms less then 2 weeks apart. Your male was the only male in the tank. Maybe the # of mates is limited by his number of claspers, maybe he's a "really free spirit", but one thing I'd count on is he's not gonna pair up and be faithfull.
i saw my male motoro knock up a female hystrix then 3 weeks later knock up my other hystrix, then 3 days later knock up my motoro... so they really can get around!