Hi Sam,
This does happen with some pairs. It’s best to see if they can work it out since they are budgies, but if she is drawing blood on him, then he needs to be removed. It might mean she can’t follow through with the chicks, but she can kill him if she is attacking him badly enough to cause him to bleed. Sometimes a brief separation works, but in some cases, the pair can’t be put back together. Not all birds make good breeders, and when you have an overly aggressive hen, it’s best not to try to breed her again. It’s hard for a single bird to try to incubate eggs and care for chicks, and there is nothing you can do to make her take the male back if she keeps attacking him.
Thank you for asking Lafeber,
Brenda