The relation between man and woman becomes lawful by contracting marriage. There are two kinds of marriages: Permanent marriage and temporary marriage
In a permanent marriage, the period of matrimony is not fixed, and it is forever. The woman with whom such a marriage is concluded is called da'ima (i.e. a permanent wife).
In a fixed time marriage (Mut'ah), the period of matrimony is fixed, for example, matrimonial relation is contracted with a woman for an hour, or a day, or a month, or a year, or more. However, the period fixed for the marriage should not exceed the span of normal lives of the spouses, because in that case, the marriage will be treated as a permanent one. This sort of fixed time marriage is called Mut'ah or Sigha.
If a woman with whom temporary marriage is contracted, makes a condition that her husband will not have sexual intercourse with her, the marriage as well as the condition imposed by her will be valid, and the husband can then derive only other pleasures from her. However, if she agrees to sexual intercourse later, her husband can have sexual intercourse with her, and this rule applies to permanent marriage as well.
Yes, some jurisprudents have said that if the urf (custom) of people is such that the temporary marriage contract is concluded with the supposition that there should be no sexual intercourse and that it is intended only to help the parties to the marriage to get acquainted with each other and to have minor relationships and the girl's father also consents to the contract on this ground, they (jurisprudents) have said that in this case no sexual intercourse should take place.
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For further information in this regard, you can refer to:
Index: Temporary Marriage, the Best Solution, question No. 695 (site: 743).
 - Tawzih al-Masail (with annotations by Imam Khomeini), vol.2, pg. 449.
 - Ibid, issue No. 2423.