Does a husband's oath to not have intercourse with his wife until she prays regularly constitute li'an, and what are the consequences?

An oath to abstain from conjugal relations with one's wife is an ila'. Here, it is conditional upon her commitment to prayer. If she commits to it, he may have intercourse with her without breaking his oath. If she does not commit, he has two options: either he has intercourse with her, in which case he must offer expiation for breaking an oath (kaffarat yamin), or he abstains from intercourse. In the latter case, the wife may refer the matter to a judge, who will set a four-month deadline for the husband to either resume relations or divorce her. The husband is advised to engage in intercourse and offer expiation if abstention proves ineffective. The wife is advised to maintain her prayers and obey her husband to avoid marital discord (nushuz).