Honestly, like it wouldn't have been totally normal to tell your best friend the girl he's crushing on is your ex that cheated on you. Zero sympathy for this dude, he makes his own problems by being such a doormat.
Gee I wonder what would happen if Nao straight up told Suzuka that she "cheated" on him with 3 imaginary guys, left him in dark for years, and then told him it was a dumbass lie, and then act like nothing happened.