I'm also can't have sex with T'Ris. Everything is set. Quest is telling to send T'Ris to Nimhe for training, but I can't! No such option in any dialog. :(
I also gave her 3 times drink, and nothing! I don't understand what to do.
UPD. Emmm, not after Astropolitn, but after Stardust - she agree to go to training. :0