It's no secret that people can feel insecure in relationships. This can manifest in many ways, but when it comes to intellectual insecurity, sometimes there is nothing you can do to make your partner feel secure in their own intelligence. Perhaps it's all in their head, in which case, this person is too insecure to date. Whatever you do, do not dumb yourself down for this person. Or perhaps none of this in their head, and your partner really is not the brightest bulb. If that's the case, depend…