Have you tried reminding yourself of the pain that you had to go through during your past idealizations, only to finally let go of your previous idols in misery?
For example, I once spent months following an ex-bf around. I was completely obsessed with him! I'd call him several times per day, try to meet whenever I possibly could, and spent A LOT of time fantasizing about "what if he loved me too?". I never liked to think about the pain that brought on my obsession. Never thought about the reality ~ that I didn't mean squat to him, and he couldn't have possibly cared less about me. It took several months for me to see this reality, and when I did I hurt even worse.
Since that time in my life, I've never again devoted nearly as much of myself into any romantic relationship that I've been in. I automatically remind myself of how everyone has ulterior motives...always! Therefore, he isn't perfect. That's not to say that I can't be with men, it just says that I don't completely trust them. I will not give them my all. They will have to prove themselves worthy before I fully let go again.
I don't know if my perspective helps you at all. But, I sure hope that it does! Idealization is never healthy for you. You merely close your eyes to the flaws until it hurts too much to keep closing your eyes.

Remind yourself of that whenever you find yourself daydreaming obsessively and thinking that the person is absolutely perfect.
Btw,

to Psych Central!