I have much the same problem as you, Doomsday, though things seem on the improve as far as my attitude is concerned. I'm not sure how old you are, but I think the tendency to go for the types of guys you mentioned comes from emotional immaturity, which would lead me to believe that the problem is less and less prevalent with older women (though obviously you need to be close enough in age to relate).
One thing you may want to try is when you approach/woo a girl is to start with a mindset that places less emotional weight on romantic success with her - "Hey, wouldn't it be nice if 'x' wanted to get together some time" might work better than "I must have 'x', my life is not complete without 'x'". It allows you to be somewhat "freer" and more confident around the girl of your affections when you aren't afraid of having your heart cleft in two if you "fail".
On the subject of "failing", when you do "fail", one philosophy that may help would involve attributing the blame for you two not becoming an item to her rather than yourself, ie: "Why would I want to be with a girl too foolish to see my worth?" This may not be the best philosophy to use if you intend to be "just friends" with her, but it may help.
Hope something in there made some sort of sense.