Birds of feather flock together? is that healthy?

I've started to think a lot about differences in opinion, when too much difference starts affecting relationships (or does it at all) and are opinions build on valuable foundations or not so much (if I can say so).

I know a person who has political opinions and views that are so far from my own, but I enjoy listening to his  point of view, discussing issues with him and challenging his views based on my own opinions. But I have been thinking a lot lately about the future and how our opinions and political views can impact our relationship, will it be a challenge? Because the people we associate the most with are the people with similar worldviews as you do, right? Will they be as open minded as I am to discuss and argue and listen and acknowledge?
I want to believe so. But i think it is an interesting thought.
I do not know a lot of couples who have total opposite political views.
I do not know a lot of best friends who do not agree on issues.
of course, no one has exactly the same ideas and views (if so, that it is not their own in my opinion). But I still think people flock to like-minded people.
Or am I wrong?
I dont know any politicians who married someone from the opposition, not here in the western world, or in other country (fair enough I havent done an extensive research).
But if we only associate with those who are similar to ourselves, with similar views and believes, will we ever learn, will we ever challenge our thoughts only to make them stronger or find new paths to believe in?
And isnt that a challenge for our world?
Does that not just lead to impatience and intolerance ?

I dont know.. but that is my opinion.
I would like to hear yours!

- with love -