This does happen with some pairs and the best solution for now is to swap them out every 12 hours to let one rest while the other sits on the eggs. If the eggs hatch, hopefully the need to feed the chicks will calm the male down. If the eggs do not hatch, I would split the pair up for a few months and then try to reintroduce them. Not all birds will make good breeders. Some will start out good and then get bored with it and this can result in the aggression you saw. One theory is the male wants to mate again and the female does not since she is sitting on eggs. Stress or perceived threats can cause this – breeding birds need privacy and should be in a room where there are no people or other birds. You should only be checking on them 2 or 3 times a day to make sure they have enough food and are doing their job. Many breeders use nanny cams now. If there are other birds in the room, especially other breeding birds, there needs to be space between them and a visual barrier is recommended. There are many articles online that discuss mate aggression, but mainly, there seems to be no single cause and sometimes it cannot be remedied.
Thank you for asking Lafeber,