Of course. If people's basic cultural assumptions are greatly different, finding compatible beliefs is difficulty, unless one has great tolerance for differences. In addition there are different norms for behavior, causing similar conflicts.

As long as both are flexible, it would add to it. Rigidity would destroy it.

I think it depends on the couple's joint commitment to make things work, but some (differences) would just be impossible to overcome for me, but that would be more societal mores and just as prevalent in my own culture as others.

Strongly.

I was married to a Brazilian and it was fantastic. The difference in cultures made it fun and exciting! I got to stay in Brasil for two months and I wanted to stay and live there so badly. Good times

It comes down to respect

Not at all. It just comes down to the person. In the Navy I knew many healthy and successful couples that were of completely different backgrounds. Now if it is a culturally religious difference, they may have a bit harder of a time squaring that one up.

It's something I'm curious about. Actually my most successful relationships have been with women with a different cultural background to my own, bith were from a completely different country. But, I'm also curious about potentially smaller cultural differences like class or political affiliation.