A: Can you imagine showing a computer mouse to someone a hundred years ago? What would they think about it? They might use it as weapon or may try to use it as a doorstop. But they would never consider to use it as we use it. Why? Because our reference points are completely different from theirs.
Now what might be of interest to you is discovering which reference point you are comparing against when you think about changing this guy. And I bet you already know the answer to that question. So what I am really wondering is what all are you missing about the guy you are with now?
I'll give you an idea of how it can work and the way you do it may be a bit different. One way is you hallucinate some other guy, and this imaginary guy is always next to the real guy in your life. They have to be next to each other so you can constantly compare and tweak the real guy to match the image of the hallucinated guy. And one day you hope that the real guy will become identical to the hallucinated guy and then he can step into the hallucinated guy's shoes and bring him to life and into your life for real. But all that means a lot of work for you and it's all for a feeling that you think the hallucinated guy will create within you.
So your two simplest options are to get rid of the feeling all together or attach the feeling to the real guy "as is". Being in love with an illusion or an idea will always lead to disappointment when compared with reality. The ups and downs of life is what makes it real. We evolve as a result of the challenges we overcome. Every relationship is an opportunity to learn about another person, human behavior, relationship dynamics, and most importantly yourself. So in the meantime, enjoy the ride!
-Oz