Hi Sivan.
They pick their own mate in the wild, and sometimes they simply are not compatible with the mate we choose for them. If both birds are at least 2 years old, and still have no interest in each other, then the best thing to do is find a new home for one of them. If you are going to breed birds, you need space and you need extra cages. Sometimes even a bonded pair will fight and you need to separate them temporarily. Sometimes a pair will not stop breeding. They must be rested for 6 months between each clutch. This may mean that you have to separate them. And if you did have success, you need another cage for the chicks, until they are ready for new homes. The chicks have to be separated from the parents as soon as they are weaned, or the parents will pick on them. Older chicks can’t live with the parents or they will try to breed and you can’t allow related birds to breed. It sounds like you are best just having one bird and not trying to breed, but regardless, this pair needs to be split up before the fighting gets too vicious and one of them ends up dead.
Thank you for asking Lafeber,
Brenda