Legend of Fu Yao - The best example of a ride or die OTP I could ever give. I will admit the second FL does play a significant role, but only for a few episodes and it only makes the budding relationship stronger. And maybe wanting them to show the OTP living their normal lives might be a stretch, but only because this drama isn't set in a world where they have "normal". But even with those caveats, I think you'd be hard tasked to find a couple with more devotion, support, and understanding than this one. The female lead is also amazing and independent.
Memory Lost - Series 1-3 are full of amazing chemistry and they're definitely a ride or die couple.