随着中国经济社会的高速发展，夫妻财产关系呈现出愈发复杂化的趋势。婚姻契约观的发展和个体本位意识的觉醒导致实践中涌现大量夫妻忠诚协议纠纷，与传统婚姻家庭观的冲突令其效力备受争议，而目前尚无司法解释对其效力认定作出统一指引。本文采用实证分析方法，通过整理分析主要集中于2012年至2019年间的我国130件夫妻忠诚协议相关裁判文书，发现当前司法实践对此类协议的效力认定有明显分歧，法律适用上存在冲突矛盾，同案不同判现象较为突出，裁判机关搁置效力争议时有发生，对违约责任的调整标准也不甚明晰。为应对司法实践中的痛点，本文对忠诚协议的法理基础进行了梳理。作为此类协议的基石，忠实义务可作为协议内容对夫妻双方产生约束。夫妻相互忠实是婚姻法倡导的一项基本原则，并非单纯的道德义务。婚姻法不禁止当事人订立符合婚姻法精神与原则的协议。在夫妻财产精细化区分、个体人格独立与意志自由在婚姻关系中不断凸显的今天，以忠实义务作为协议内容也与公序良俗原则并无冲突。在法律适用上，本文主张不应将婚姻家事法律与其他民事法律尤其是财产法完全割裂开来。夫妻忠诚协议往往混合了身份行为与财产行为，对于涉身份行为的约定如亲属法有规定则优先适用，对于涉财产行为的约定，在考虑到婚姻关系身份特殊性的基础上参照适用民法总则及财产法。同时，虽然违反忠实义务可能导致离婚损害赔偿，但离婚损害赔偿事由的限定性常常令受害方不能得到充分的救济。作为当事人意思自治的结果，夫妻忠诚协议起到了补充法定离婚损害赔偿制度不足的作用，违反夫妻忠诚协议的后果不应与离婚损害赔偿混为一谈。本文采用类型化效力分析路径，基于大量实务案例将夫妻忠诚协议分为身份型夫妻忠诚协议与财产型夫妻忠诚协议。对于以违约方无条件同意离婚，或丧失对子女的抚养监护权利等为违约责任的身份型忠诚协议，由于其所涉的身份行为在亲属法上多有强制性规定，一般不宜赋予其效力；对于以过错方丧失夫妻共同财产或支付违约金为违约责任的财产型夫妻忠诚协议，如符合民事法律行为及合同的生效要件，一般应认定其有效，且应与夫妻财产制约定及离婚协议区分开来。最后，本文基于司法实践及民事法律原则总结了财产型忠诚协议违约责任调整时的考量因素，包括：当事人所在地的收入水平及过错方的收入情况、过错方违反忠实义务的过错程度及双方感情情况、是否影响过错方履行抚养子女或照顾老人的义务、与离婚损害赔偿的竞合、夫妻共同财产分割与违约金的竞合。

With rapid development of China’s economy, marital property relationship has become more and more complicated. The evolution of the concept of marriage contract and the awakening of individualistic consciousness have led to the emergence of a large number of disputes on spousal fidelity agreement in judicial practice. At present, there is no judicial interpretation to establish unified guidance on the legal effect of spousal fidelity agreement. The conflict between spousal fidelity agreement with the traditional concept of marriage and family has made its legal effect controversial. This thesis adopts the empirical-analysis method, and by collating and analyzing 130 cases related to spousal fidelity agreement mainly dated from 2012 to 2019 in China, it finds out that Chinese courts have different views of the legal effect of spousal fidelity agreement in similar cases, and the application of law in these cases has conflicts. Determination of spousal fidelity agreement’s legal effect is ignored in some cases, and the standard for adjusting the liability for breach of such agreement has not been clear. In order to solve these problems in judicial practice, this thesis combs the legal basis of spousal fidelity agreement. It holds that obligation of fidelity can be stipulated in agreements to restrain spouses. As the cornerstone of spousal fidelity agreement, obligation of fidelity is not a pure moral duty but a basic principle of family law, which does not prohibit a couple from entering into an agreement that is in accordance with the spirit of it. With the refinement of marital property system, and the increase of self-independence and freedom of the will in marriage, obligation of fidelity as the content of an agreement does not conflict with the principles of public order or good customs. In terms of application of law, this thesis argues that family law should not be completely separated from other civil laws, especially property laws. Spousal fidelity agreements often mix identity behavior and property behavior. In agreements related to identity behavior, family law is preferentially applied if such behavior is regulated by it. For property-related agreements, the general provisions of civil law and property laws can be conditionally applied with the consideration of spouses’ special legal status under family law. At the same time, although the breach of obligation of fidelity may lead to divorce damages compensation, the limitation of the causes of divorce damages often prevents the innocent party from getting effective relief. The spousal fidelity agreement, as a result of spouses’ autonomy, complements the statutory compensation for damages in divorce. The consequences of breaching a spousal fidelity agreement should not be confused with compensation for damages in divorce.After clarifying the foregoing legal basis, based on the analysis of a large number of cases in practice, this thesis divides spousal fidelity agreements into two types, namely, identity-based spousal fidelity agreement and property-based spousal fidelity agreement, and conducts typed analysis. As for the identity-based spousal fidelity agreement in which the wrongdoer shall unconditionally consent to divorce or waive custody or guardianship, due to the compulsory provisions of family law, it is generally not appropriate to give effect to it; as for the property-based spousal fidelity agreement in which the wrongdoer shall lose certain joint property of the spouses or pay liquidated damages to the other party, if it complies with the effective requirements of a contract and a civil legal act, it should generally be determined as valid and should be distinguished from spousal property agreements and divorce agreements. Finally, based on judicial practice and the principles of civil law, this thesis summarizes the factors to consider when adjusting the liability for breach of the property-based spousal fidelity agreement, including (a) the income level of the wrongdoer’s locality and the income of the wrongdoer; (b) the degree of the wrongdoer’s fault in breaching obligation of fidelity and the couple’s relationship; (c) whether the fulfillment of the agreement will hinder the wrongdoer’s obligations of raising children and/or caring for the elderly; (d) concurrent compensation for divorce damages; and (e) concurrence of the division of joint property of the spouses and the liquidated damages.