We were discussing our fantasies. I said I'd never really had any and I'm happy with just standard sex. When I asked DP she stated perhaps a threesome. I think I looked surprised and said really? She replied yes. I know she's had them in the past. With 2 men and also a man and woman. I said so you want to invite someone into our relationship and sleep with them and she said don't you think it would be fun. I said no I wouldn't feel comfortable with it if I'm honest. I said perhaps if I wasn't in a relationship but I felt it would ruin a relationship in my opinion. She then back tracked a bit and said we'll i only said it because I thought you would like to do it and now she's saying she wouldn't like one.
Aibu to be concerned DP wants to explore outside our relationship?