If I understand correctly this is her first time cuckolding you. Also assuming her first time cuckolding anybody but not her first BBC so she may want a little bit of privacy so to speak with him just to get comfortable with the whole cuckolding perspective. She may not feel you are ready to see her responses to BBC as she already knows how she's going to respond and is slowly breaking you in so to speak by only letting you listen at first. Just make sure that she knows that as everybody gets more comfortable that you are going to want to be in the room and possibly having a very up close and personal View not from sitting in the chair in a corner