It sounds like your male is a very people oriented bird, so he really does not need a mate. Birds do not have friends. Young birds will live in a flock and interact, but mature adult birds will have one mate and will not have much interaction with flock members. A tame bird treats humans like flock members. But if you get him a mate, he may eventually bond with her and if he does, he is not likely going to be tame with humans anymore. Also, adult birds do not need a nest unless they are a bonded pair and it is nesting season. Adult birds do not sleep in a nest in the wild. A nest is used only to lay eggs in and raise chicks. When you give a nest to a pet bird, it will do what your male is doing and start acting hormonal. So go ahead and take the nest away from him and you will not have the problem anymore.
He most likely attacked the female because she was younger than him and may not be mature enough. Plus he is a “people bird” and doesn’t care about having a bird mate. Again, if you want him to remain a tame pet, he does not need a female. And since you have had him for so long, and have no idea how old he is, he is possibly too old to breed anyway. I feel like he needs to be kept as a pet, no nest, no mate. You are just bringing on problems instead of making him happy.
Thank you for asking Lafeber,