I am sure Charles never loved Diana, it's worldwide known that Camilla was the 1 who advised charles to marry diana, they both thought she was not an obstacle to their relationship, true Queen Mum and Lady Fermoy, di's grandmum, thought of a wed btw Charles and Di, but Camilla gave her lover her ok, so while I think di was in love with Charles, he was not, all he wanted from her was a heir, when Harry, the spare heir, was born, the realtionship btw the couple soon ended, and Cam became again, she had never left indeed, officially his lover.