Poe has sort of guided Finn and Rey in intimacy since both haven't had opportunities or the psychological state to pursue it.
Rey and Finn, relying on Poe, have danced around each other until Poe is gone for extended period of time.
They have a confrontation, angry and emotional. Through it, they admit how devoted they are and will be to each other. They have a passionate and emotional first time with just them, not knowing that Poe arrived early to witness the confrontation and their first time. He watches as they finally be one together.
Rey/Finn/Poe; Poe is a voyeur to Finn and Rey's first time
Rey and Finn, relying on Poe, have danced around each other until Poe is gone for extended period of time.
They have a confrontation, angry and emotional. Through it, they admit how devoted they are and will be to each other. They have a passionate and emotional first time with just them, not knowing that Poe arrived early to witness the confrontation and their first time. He watches as they finally be one together.