在台灣，婚姻制度的變遷顯而易見，而對於伴侶關係品質的研究，目前相關的不是僅單純各別探討同居或結婚，就是單純探討以同居經驗來區分已婚者的關係品質差異。因此，本文將使用台灣青少年生命歷程資料(TYP)，其抽樣樣本來自24-32歲的成人，以同居經驗、結婚意願為依據，將伴侶關係型態分為四大類，即婚前有同居的已婚者、婚前無同居的已婚者、同居有結婚意願者、同居無結婚意願者，共有762人（男性352人，女性410人），並以選擇性因素、制度性因素、承諾性因素三大論點，去比較與解釋四大類伴侶關係型態的快樂程度差異，為本文主要研究目的。
一、 72%是已婚者、28%是同居者，同居人口比例並不高。
二、 在與伴侶快樂程度的分佈當中，雖然不快樂僅占全部的3.6%，但可以發現女性不快樂的人較男性多。
三、 婚前有同居的已婚者與婚前無同居的已婚者相比，兩者之間的快樂程度無明顯差異。
四、 與有結婚意願的同居者相比，無結婚意願的同居者之快樂程度會較低，亦是四類中最低。
五、 對有結婚意願的同居者而言，在未控制任何選擇性因素時，其快樂程度是四類中最高的。但在控制個人特質與原生家庭等因素後，發現其快樂程度與已婚者群並沒有顯著差異。
Using data from the Taiwan Youth Project (TYP), this research examines the ways in which union types affect the relationship happiness of coupled young adults aged 24-32. Specifically, married and cohabiting respondents are divided into four relationship categories: married respondents that ever or never lived with their spouses before the entry into marriage, and cohabitors with or without marriage plans.
The final analytic sample size of this research consists of 352 young men and 410 young women. The analyses show several important empirical findings. First, approximately 28% of the 762 coupled respondents were in a nonmarital cohabitation relationship. Second, on average, the respondents reported high levels of relationship happiness, although women were less happy than their male counterparts about their relationships. Third, relationship happiness varies across the union types. Specifically, while other family and individual characteristics were not taken into consideration, the cohabiting respondents intending to marry with their partners reported the highest levels of relationship happiness. However, with all things being equal, there was no significant disparity in relationship happiness between marrieds and cohabitors with marriage plans while those in cohabitation relationships but without marriage plans reported the lowest levels of relationship happiness. Finally, the contributions to the study of family change and implications for related social policies in Taiwan are discusse
