Sentence 1: Raphael didn't know he was gay until he was sixteen. 
 Sentence 3: The problem was that Matt had a girlfriend 
 Sentence 4:  So Raphael stayed silent for years 
 Sentence 5:  Only when they were in college did Matt admit he was gay too 
 Option 1: At that time, he only admitted it to his best friend Matt. 
 Option 2: At that time, he couldn't deny his attraction to Matt.