My gf (26 F) wants to try bringing in another girl to suck my (29 M) dick together and possibly have sex with. It feels like a bad idea to me but she doesn’t understand why I’m not more excited. I guess I like the idea in theory but I’m not super into the idea of having others involved in our sex life honestly (ours is great and we are both satisfied). She’s beautiful but not super secure in her body, and I also feel more anxiety than excitement about the idea. It feels like it could cause a significant amount of disruption to our relationship. She is astonished I’m not immediately so excited and desperate to do this but I can’t really articulate why I am not! She just keeps saying it’s every man’s dream to get his dick sucked by two girls but honestly I’m happy with her! Anyone relate or gone through similar?
EDIT*
We are in long term relationship. Live together, been together a long time and very comfortable and aligned with the future. Both very happy sexually and open communication about everything so we try stuff together regularly for fun. Both agree there is no problem in our sex life it’s just a fantasy for her. it doesn’t seem like it stems from insecurity? She knows she is more than enough and is very confident in our sex life together. But brushes past me raising potential for insecurity/problems and thinks as long as we all stay involved it will be a great experience for all… She says she’s not bored or anything but just the idea of involving another girl seems to turn her on and she doesn’t get why I feel like I sense danger and I’m not good at explaining why either! * also she knows and has always known I would never ever be comfortable involving other men or anything like that so it isn’t like she’s trying to inch towards that scenario – she knows and respects that’s a hard boundary and seems to have no interest in that anyway, just sharing me with a girl.