I suspect that he may have been heavily bonded to a female before you got him. He now seems to have transferred that bonding to you. And his hormones may have been the reason why he was given to the breeder in the first place. Unfortunately for you that may have been the best place for him, in an aviary where he can breed, which is what he obviously wants to do. He would probably have been better going to a male owner and not a female, and no females around him. He may calm down after breeding cycle.
Unfortunately I really cannot suggest anything that you can do to calm him down. I suspect he was sold originally to a woman and that there where no men in the house or only the occassional male visitor, and the woman showed him lots of affection and he wasn't able to socialize with both sexes. When I was hand raising cockatiels I always made sure they were socialized with both sexes of humans and not just me. Even my pet Cockatiel would go to everyone even though he did prefer me and he was never aggressive with anybody.
Sorry I can't be of more help.
Unfortunately I really cannot suggest anything that you can do to calm him down. I suspect he was sold originally to a woman and that there where no men in the house or only the occassional male visitor, and the woman showed him lots of affection and he wasn't able to socialize with both sexes. When I was hand raising cockatiels I always made sure they were socialized with both sexes of humans and not just me. Even my pet Cockatiel would go to everyone even though he did prefer me and he was never aggressive with anybody.
Sorry I can't be of more help.