Sgt. Peter Best's Lonely Hearts Club Band Syndrome
Psychological despair after passing up an opportunity that would have yielded positive effects because it seemed unsafe. The term is named for Pete Best, the original drummer for the Beatles who dropped out of the band because he believed the band wasn't going to make it. The term also creatively uses the name of the Beatles' hit song, "Sgt. Pepper's Lonely Hearts Club Band". The term gets it's origins from a play named "Sgt. Peter Best's Lonely Hearts Club Band Syndrome".
When she started seeing someone else, he had a bad case of Sgt. Peter Best's Lonely Hearts Club Band Syndrome because he didn't ask her out first.