In Shi3a ithna `Ashari fiqh, it's a unanimous ruling that unless some form of contract was entered into at the time of nikaH or the wife herself permits, a husband cannot refuse sexual intercourse with his wife beyond four months.
The following is by Sayyid al-Sistani:
2427 It is not permissible for the husband to abandon sexual intercourse with his youthful, permanent wife for more than 4 months, except when sexual intercourse is harmful to him, or involves unusually more effort, or when the wife herself agrees to avoid it, or if a prior stipulation to that effect was made at the time of Nikah by the husband. And in this rule, there is no difference between the situations when the husband is present, or on a journey, or whether she is a wife by permanent or temporary marriage.
This is by Sayyid al-Khoei (ar):
2427 It is not permissible for a man to abandon sexual intercourse with his young permanent wife for more than 4 months.