if you want the real game check Kaito's other game -
School Game / Sandbox, Simulator, RPG
like, its a happy-sad moment for Nicole. on one hand she's getting the attention she wanted, on the other she knows MC is hurting over Irene. As for MC knowing he shouldn't be trying to distract himself from Irene by using Nicole. basically his feelings for Nicole VS the pain and need for distraction he's feeling.
You are not supposed to enjoy it actually, its meant to make you empathize with how they are feeling in that moment/situation.
nicole is trying to at least feel wanted over irene, EVEN THOUGH she knows its not exactly like that. mc is mourning the loss of his lover's memories, THEIR memories.
Its to emphasize the sense of loneliness and loss everyone is feeling there.