Yea I told them when they got married that their world views will be a huge contention in their marriage. 

About a year ago he said to my other mutual friend that I hate to admit it but OceanSlim was right. 

Marriage should be built on shared values. It's not impossible to do so without but it's a terrible starting point.  

 You can share values and still prefer different parties, for cultural reasons, age-differences, or something. 

 Parties and cultures typically align with world views and thus values.