How does growing up in a poor home environment lead someone to develop narcissistic traits?

Should I consider giving a romantic relationship a try with my childhood friend, even if I never thought about her that way before? What factors should I think about?
Being single is great. I get lonely at times, but I know and control how my day is going to go. Why is romance hard to find?
Of course, ideally, we prefer to be in fulfilling relationships. However, when that is not the case, do you prefer to be in an unfulfilling relationship rather than be alone, or vice versa?