Hehehehe, now THAT has me thinking....would they be using you for sex because they know it's not going to work out? Or would they jump you on the first date because they know it's meant to be?
I'd have the same problem with a psychic, Wiggles. Plus, a psychic would know I was in a foursome a couple weeks ago, and went from bi-curious to bi last night, whereas a normal significant other has no clue.
1) They'd know how good you would be before you would
2) You wouldn't have to tell them when you were cumming
3) She wouldn't have to worry about date rape
4) Simultanious Orgasms would be a piece of cake
And immagine this one...
5) You walk up to her in a bar, she looks you over and lights up a post-coital cigarette right there