Marrying someone, espousing someone, is among other things having/building a common perspective of the world, and of how you want to grow old in it.

If, before getting together, your political views are hard to reconcile enough, it’s highly likely your other views are such as well.

If one is so shallow to concider political affiliations as crucial, especially in the US, where the two parties are both sucking off the corporations, bankers, and their billionaire friends, are warmongering, and are feeding their voters BS, while making every day life for the average person even shittier with neoliberal policies ever since the 70s, I wouldn't want to know what else they find crucial...

Politics is much more diverse and complex than binary, and much more serious than the play some incarnation of parties do here and there.

Your political preferences, whatever they are, process from principles (most of the time, though) and from circumstances, to which you react. So they are likely in line, somehow, with both your character and your philosophy of life.

That’s not shallow at all, only a significant enough signal.