How big is the tank? And how many hiding places do you have?
Unfortunately it is just what male apistos do they are nasty to females, if you think that is nasty you should see how the female gets when she lays
Sometimes adding dither fish like guppies or danios or something like that for them to take their agro out on can help, otherwise a descent sized tank and lots of hiding places, separating them if she is getting injured.