Aaah, now I get how this is going to end. He'll kill her... by turning off the machine that keeps her 95-year-old self alive, after she's looked back on a life filled with love and joy at his side and finally understands true contentment. They're surrounded by their children, grandchildren and great-grandchildren crying bitter tears. But Maou won't cry, because he knows they will surely meet again in the next cycle, and they'll get to do it all over again.
But I don't mind watching them fuck a bunch while she's still young and hot.