Question: Does a married man have a Biblical obligation to physically please his wife or is it just something he can choose not to do?
Answer: A man does indeed have a Biblical obligation to please his wife – this is deduced from Laban’s admonition to his son-in-law Jacob to properly care for his daughters (Gen. 31: 50). There is actually a reference to this requirement in the Ketuba (marriage document) to which every traditional Jewish man obligates himself in writing at his wedding! See the Talmud (Kesubos 47b). The precise (and regular) circumstances that trigger this obligation are also well defined by Torah law (See Shulchan Aruch Even Haezer section 76).
I hope this helps.
Rabbi Boruch Clinton