Princess Diana and Prince Charles met each other when Diana was only 16 years old. There was an age gap between the two. By the time Prince Charles returned home from the Navy and he and Princess Diana got married, he was 32 and she was only 20 years old.
Although they got married, they weren't in love with each other from the start and that didn't change as their marriage progressed. In fact, things got much worse and Diana was never happy with Charles and he wasn't happy being with her either.