Clark Kent and Lois Lane
I love Superman since I was a child. The concept of immortality and invincibility is just too cool for a boy, though he had weaknesses with Kryptonite and Lois Lane. Kryptonite is Superman's Achilles' heel, and very often used by his enemies to bring out his vulnerability, similar to Lois Lane. She is Superman's primary mortal love interest and quite often I wonder why a Super-being like him, doesn't date Wonder Woman, Supergirl (Superman's cousin) or some other less frail Super Hero.
So very often I wonder why did Superman put himself into that situation of always having the need to save Lois. She is often depict as a determined, strong-willed person who often gets herself into trouble from her career as a successful journalist. Till I hit my teens, I've come to realised it was for viewer-ship by the creators to create this fragile mortal which often require Superman to rescue. So no trouble, equals no comic prints.
But as I grew older, I realised that everyone has their Kryptonites and Lois Lanes. Their weaknesses and vulnerabilities somehow bring out the human in all of us. The constant search for that weakness and the compelling love story is probably in-born in all of us who seek to be Supermen, purveyor of justice, inequalities etc.
Then the selection for Lois Lane, how does one define the chief love interest? Surely there are options and choices being Superman, able to fly around and quite often a charming individual if not strong and hunky. In my case, perhaps more chunky than anything else. I believe we all have our poison and the need to have someone, a better half; someone who makes you want to be a better person. That is perhaps the most difficult part, to define and know what you want, what makes you want to be a better person. As you grow and change in perspective with respect to life, you make changes based on experiences and on forward-looking goals. So as I often tell my friends, whatever works for you - Beauty is in the eye of the beholder and if the beholder is Superman, his standards are unique to him even if all he wants is mere mortal.
I believe my Lois Lane is independent and dependent at the same time, quite often requiring a rescue or two; that she is a mother figure to future Superboys; that she complements Superman's lifestyle and goals; that she will hold him back if needed; that she has a mind of her own; that she is who she is so even if the world goes insane; that she is super in many ways only Superman can see and would like to have in his journey in life. And finally, that she makes him feel like a Superman in his own way accepting who he is, everyday despite the weight of the "world" on his shoulders - that makes him want to be a better, super person.