Why would a good friend you've known for many years rape you?

DanaPonds

My good friend (26 F) was raped several years ago. She was 19 at the time. The sad part is she knew him practically her whole life. This wasn't a stranger or boyfriend of 2 years. This was her childhood playmate. Both met when they were 5 year-olds. That was like a brother to her. Both sets of parents were best friends too. They grew up together in the same town.

Their platonic relationship came to an end when he started having obsessions about her after his 18th b-day. He got rejected by several girls at school, never got a date. Then the following year of no luck with any date, his obsession grew, then he suddenly changed out of nowhere and raped her. She told him to stop many times and tried to remind him to remember their good times but it fell on deaf ears. He still proceeded and stole her virginity.

He's already in prison. He admitted to the charge. Obviously this has impacted her so much. She doesn't trust anyone except me, her two other close female friends and her family. She never saw that coming, never expected that from him. Why would a long-term childhood friend do that?

Updates
8 mo
Even though it's been years later since, she can't really comprehend what on earth happen, why and if she ignored signs more or if their whole entire friendship was a lie from the start, etc.
Why would a good friend you've known for many years rape you?
8 Opinion