1) I’ve heard that a wife cannot refuse to have sex with her husband. Is it the same for men? Can a husband refuse to have sex with his wife without any valid reason?

2) Why aren’t these rules same for both husband and wife?
for e.g a wife wants to have sexual relations more than every four months and husband is not fulfilling her desires isn’t he commiting a sin?

1) “It is not permissible to neglect sexual relations with a young wife for more than four months, unless there is an excuse like unbearable difficulty or harm [in fulfillment of that duty] or unless she agrees to it [that is, forgoes her conjugal rights] or if it was part of their agreement at the time of marriage.

2) This is responsibility of both