It’s interesting because this also happens in other languages. In Dutch we only use couple (koppel) for people in a relationship.
If you are talking about other things we use “pair” if you have two. But over time people also started using pair wrong, so someone saying “ik heb een paar knikkers” I have a pair of marbles, can still mean he has 5 marbles.
In practice people usually just say I have two marbles when they mean exactly 2.
I’m not from the US but I would describe myself a a left leaning centrist. The parties I voted for in the last 5 elections where all center left.
If you map the parties based on left/right and progressive/conservative my vote is definitely center left and high progressive.
The US has a political system that sucks, where you only have 2 real options. A system where multiple parties have to form a coalition gives you the voter many options.