The final solution
The crafty Hades learned this agreement and tricked his reluctant bride, who was crying all day and night from despair, to eat a few seeds of the pomegranate fruit. This was the food of the Underworld and every time someone ate even a few seeds of this, then, after a while, he would miss life in the Underworld. When the gathering in front of Zeus took place and Persephone was asked where she would like to live, she answered she wanted to live with her husband. When Demeter heard that, she got infuriated and accused Hades that somehow he had tricked her daughter.
A great fight followed and Demeter threatened that she would never again make the earth fertile and everyone on Earth would die. To put an ed on this quarrel, Zeus decided that Persephone would spend half months with her husband in Hades and half months with her mother on Olympus. This alternative pleased none of the two opponents, nevertheless that had no other option but accept it.