I'd agree that it would be relationship ending if a couple had issues on all politics, but an individual's politics are comprised of multiple positions of many issues and I doubt that all successful relationships are so because they have no political tension. Political difference is natural - it's nothing more than a debate. And just as some debates don't resolve to clear answer or a "right or wrong", nor will political differences in both a couples' relationship, and people in Love and "society" or a particular "culture"...