Until recently interfaith marriages and romantic relationships were scarce. In fact only about 20% of marriage before 1960 were interfaith. Using the NFSS we estimate that 44% of all couples and 38% of married couples in 2011 had different religious traditions than their spouse or partner. While this is good news for interfaith understanding and tolerance, it may be bad news for relationship stability and satisfaction.
Using data from the 2011 Survey “How Couples Meet and Stay Together” directed by Michael Rosenfeld at Stanford University we find that differing religious traditions predict significantly higher rates of relationship dissolution (See Figure 1.) While it is unsurprising that couples whose religious views are similar have a much lower chance of splitting up, so do couples where both persons subscribe to no particular religious creed.
Couples that share religious outlooks also think more favorably of their relationships than those who are from different faiths (See Figure 2.) In fact those of the same religion were far more likely to report excellent relationship quality than were those who identified with different religious worldviews. When we control for the effects of race, income, and education the differences remain even in a sample composed entirely of married couples.
Religious differences do not necessarily spell defeat for couples just starting out. However, couples that have been together for a long period of time seem to be increasingly similar in terms of their religious views. Among couples that have been together for under two years, only 33% are from the same faith, or are both non-believers. Meanwhile, the same is true for 64% (almost double) of those who have been together 20 years or more (See Figure 3.) The trend is even more pronounced for married couples. There are two plausible explanations for this result. It could be that marriage and other romantic relationships are simply less stable when balancing divergent religious perspectives, but it could also be true that with time successful couples slowly converge toward a shared perspective. Though they might have initially had less compatible worldviews, through time they “become one” in terms of their religious perspectives. Regardless, couples who fail to converge on a religious worldview are less likely to succeed.