Nick Carter of the Backstreet Boys said he was “shocked and saddened” Wednesday after pop singer Melissa Schuman accused him of raping her and forcefully taking her virginity about 15 years ago. Schuman, who rose to fame in the early 2000s as a member of the girl group Dream, said in a blog post earlier this month that she was 18 when Carter allegedly forced her to give him oral sex and have intercourse at his California apartment.