From the Baha’i Writings:
The Bahá’í Faith recognizes the value of the sex impulse, but condemns its illegitimate and improper expressions such as free love, companionate marriage and others, all of which it considers positively harmful to man and to the society in which he lives. The proper use of the sex instinct is the natural right of every individual, and it is precisely for this purpose that the institution of marriage has been established. The Bahá’ís do not believe in the suppression of the sex impulse but in its regulation and control.
(From a letter written on behalf of Shoghi Effendi, Lights of Guidance, p. 344)