As a man who has fallen for women who were not good for me at all, I can say that if you are having problems with all the wrong guys or girls in your life (just as I had problem with all the wrong girls in my life) then it is time for some self-reflection on your walk with Christ. Until you give Christ your full heart and bring all things (including your dating life/preferences), you are going to have sin and the associated chaos thereof running rampant in your life.
The Word of God says "Seek the Kingdom first". Many of us would rather change that to "Pursue a career, education, bf/gf, or spouse first and pursue God as a secondary or co-equal goal." Set your eyes on God and He will take care of the rest. But if you try to grasp at the straws that the rest of the world around you does (and encourages you to do the same) that were never meant for you in the first place, you are never going to accomplish the great things that God wants for your life.
I encourage you to set your eyes on Jesus. If we would only do this one thing, we would see all else fall into place. Again, set your eyes on Jesus.