With my fish in the past, the tail nipping continues until the female accepts the male's attempts. Once they've spawned, he leaves the females alone until the fry are free swimming, or in my case, until the eggs have all been eaten by the other fish in the tank. The tail nipping is part of their courtship behaviour. The way you describe the male, he is in breeding mood.
When I had honey gouramis, this was how they behaved - male swims in front of the female with his nose upwards. If the female ignores him, he chases her and nips her tail. Eventually the female responds by starting to follow his towards his bubble nest, then loses interest and the male chases her and nips her tail. Finally the female follows him to the bubble nest and they spawn, they both drift apart in a sort of stupor then the male wakes up first, collects the eggs in his mouth and spits them into the bubble nest. They do this several times then the male chases the female away. The male then chases every other fish away from his egg-laden bubble nest, including the female.