"Pisces and Libra.
On their first meeting Pisceans see Librans as their romantic ideal, someone they could fall instantly in love with. Librans see Pisceans as quite beautiful and with a dreamlike quality they can not resist. There will instantly be a tremendous sexual attraction between them. Pisceans will see Librans as romantic and sociable like themselves, someone who can keep them entertained with endless laughter. Librans will find Pisceans are emotionally insecure but feel well able to cope with that side of their character.
Because of the instant attraction between these two it's very likely they will rush into a physical relationship. They are both incurable romantics and will be very well matched sexually. This all sounds too good to last and it probably is because the Piscean has deep emotional needs which the Libran is unable to cope with. Their real problems start because they will never discuss important matters like the future as the Piscean would rather drift along leaving the Libran to be serious and make all the decisions which they are unable to do.
Pisceans want to live in a dream world of their own making and Librans want pleasure with an easy life. This combination is almost impossible but if both have planets like Venus (love), Mars (desires), the Moon (emotions) and Mercury (mentality) in other more compatible signs this match can work. If not it may be that the Piscean becomes obsessed with the romantic side of life and the Libran realises the Piscean is not their equal mentally. This relationship will always be difficult but if they are prepared to work at it Pisceans can learn to be less dependent on their emotions and Librans can learn to get in touch with theirs."
quoted from
http://www.astralarts.com/pisrel.html