CHARDON, Ohio — A woman has pleaded guilty to reckless homicide for exercising her 73-year-old husband to death in a swimming pool, repeatedly refusing to let him leave the water. Surveillance video showed Christine Newton-John, 41, pulling James Mason around the pool by his arms and legs, said Middlefield police Chief Joseph Stehlik. Stehlik said he counted 43 times in which Newton-John…