If love entails finding someone who accepts you for who you are, then why does a successful relationship require change? WTF. Seriously, this has been bothering me a lot lately. As I've been contemplating certain dynamics of my current long term relationship. SO, how the hell do you guys sleep at night?

This, will never be understood by me.
No one should have to change appearance or their personality to meet the requirements of love in a relationship.
Sometimes there are behaviors that are not harmful, but bother the partner, such as checking out members of the opposite sex. Such behaviors should be discussed and possibly altered, but are not required to be changed as that would opress one's identity. These behaviors should only be changed at the discretion of the person who exhibits the behavior, should they find it a benevolent
Anyway, I'd say compromise. It's necessary sometimes. I don't know, that was just the first thing that popped into my head so I'll just stick with it:P.
As you continue along your relationship you both grow and learn to appreciate and respect and love each other more everyday that passes.
If you do not grow in a relationship together, then one will fall behind and without the 'change' for the better, sadly lost.
Its not all about the bad things that happen. Its about accepting new challenges and continuing being a loving couple.
Yes the relationship may need to go through many changes through the years. You will need to adapt to these changes and change to suit.
" love entails finding someone who accepts you for who you are" That means someone who will not hate you just for being yourself, but may or may not be irked by certain little bits.
I want to know why people say it takes hard work. It takes work, I'll agree, but it has never been that hard.