I personally don’t think people of different faiths can be good together long term. Or rather, an atheist and a theist cannot. I’m an atheist, and I have religious friends and family members I care for deeply, but when it comes to marriage and a spouse, the question of whether you are religious or not cuts to the core of your worldview.

My partner and I call ourselves atheists in that we actively disbelieve in any human created religion, and believe that all stories of “God” are metaphors different cultures have developed to try and explain the deep mysteries that we have not and probably never will explain with science. Perhaps because of our brains' inherent limitations as three dimensional, carbon based mammals. There are certain concepts we will never fully be able to understand.

As such I understand why people are religious. And my partner and I are in our own way seeking deeper answers to these mysteries, through metaphysical musings, psychedelics and metaphors.

At the same time, we recognise while our feelings of the numinous are real, our explanations and imagery are not “the real thing” but our brain’s effort to make sense of the thing it is inherently unable to fully grasp.

For us, being non-religious means that we are constantly seeking the answers to these mysteries, trying to further our understanding, while realising we will never fully know. What happens after death. Where the universe came from. What is the nature of consciousness.

For religious people, they believe they already have the answers to those mysteries. That answer being whatever God they believe in.

As such I think it would be incompatible to be life partners with someone religious. Because the outlook on the world is so different.

It’s not even about shared values of kindness, harmony, service to others, compassion etc which as you say are universal to different cultures and faiths.

I would venture to say my core values are similar to yours.

But in a marriage between an atheist and a theist, one will always have to compromise on a core belief. Or feel that their loved one disparages their belief because they don’t agree.