"Started falling in love" is not the same as "hot fantasy come to life". So she remembers working past what soured her on the relationship and remembers coming to the conclusion that the guy under the mask wasn't so bad at all. All the easier for her now to leave the mask on and live her fantasy. She knows the guy wearing the Spider-Man mask is not some kind of creep pretending to be what he's not. Like the Chameleon did to Michelle when the two of them made out with the Chameleon playing Peter. Now that his identity has been redacted from her memory, she is back to the fantasy and doesn't have to work past anything. She has it back to the way she first wanted it, so why not enjoy it as it is? She knows who is under the mask, it's Spider-Man. And that's perfect for her.