Raise your temp to mid to high 80's, feed high protien diet, add more oxygen to the tank see how that goes for the next couple weeks. if that doesnt work then pull out the smaller hait for 2-3 days then re-introduce and try the above again. I remember you saying your female was more aggressive so i would pull her or divide them for a couple days while your increasing the temp in the tank giving the male more space to claim as his own, then pull divider and they should go back to the courting and sparring ritual for a couple hours or days then she should spawn for him.