I'm sorry for the late reply! Thank you all for the encouraging words.
My boyfriend admits to his initial attraction being based on "intellect, humor, and a unique-yet-girly persona." I see him as quite the prize, even objectively speaking, so it has done a lot for me in terms of this issue. (As an aside, I feel very awkward sharing a positive perspective on myself!)
I think my creating this topic was mostly a need to vent about my frustration with insecurities. If I find an insecurity to be based on a valid concern, I don't exhaust myself with justifying it -- I only work on a solution. Otherwise, if the insecurity is difficult to justify having, I become stuck in a loop of pushing the insecurity away and inviting it back. In other words, I felt the need to complain about how my thoughts persist even though I know how silly they are, rather than the thoughts themselves.
I hoped, too, that others would be able to relate and share; I think it would have been nice to look at the problem through another window.