See, I was in the crowd of 'males and females never together' and I wouldn't have tried it with my previous males. But this boy, he is a good year older than the oldest girl, putting him around 2yrs old, so i figured older aged played a key (?). Also, the amount of times he had escaped and there being no issue, was most probably another factor that they got use to eachother.
There was an accidental spawning, seemed to happen over night but the pk girl was adamant about getting into his sectioned part of the tank

pretty big bubble nest, he was having issues wrapping her but eggs were falling, they were picking up but he destroyed the nest with his tail and dorsal fin. Was gutted, after a few hrs spawning, he wrecks it but hey ho, that's life.
if we could breed bettas, to be like other fish who have 1 male to 3 females ratio, I think it would be grand.
I wouldn't try male/male, i could seen that being an accident waiting to happen.