Look back over your old relationships and see if you can identify a pattern. You probably have a type, and a certain way that you're used to relating to your dates and lovers. Maybe it works for you; you do seek out lovers with whom you're intellectually matched, people you're comfortable talking to.
But if you're holding yourself back from truly understanding the implications of your own life and future, then a mental match with a lover won't do much to help open your eyes to all the possibilities of your life. Instead, your inclination is to stay comfortable, with your eyes shuttered to the reality of the world around you. You're probably more comfortable with telling your sweetie how you see things than you are with letting them play devil's advocate and possibly stir up questions in your mind. Are you really content with the state of your life? Do you truly know where you're headed, and what your goals are, both in your career and in your love life? If those questions gave you even the tiniest shiver of doubt or nervousness, take it as a sign that it's time to get honest with yourself about the need for change and growth -- including in your romantic affairs.