if you only have the one pair the male will always be chasing and harassing the female it is best if you add another two or three 3 females it should help to level out the aggression among females, the larger the group the less females you need to add.
many people believe they should have about 3 females to each male for example 6 males = 18 females it works just as well as having 2 females to each male = 12 females it can also work with 6 pairs or more