she's not being direct about it, but she brings the topic of a threesomeup from time to time, she's asked me if i've had one, which i haven't, and i know the only one she's had is with our housemates (this is just before we got together), to be fair, that was was when i was away sleeping with another girl, but i still feel weird about it. anyway, the idea of a threesome intrigues me some, but i'm unsure as to whether to agree to the idea, i'm quite insecure as it is, without bringing someone else into the relationship. what should i do?