I think you are discovering that women, on average, have different expectations from a sexual relationship than men. In fact, it is not weird at all to find that men are much more interested in one night stands than women. Even women who are interested in casual sex tend to want their partner to be at least open to the idea of entering into a relationship. If anything in your bio hints that you are only interested in sex, you will pare your respondent pool down to exactly the type of women you discovered to be receptive: adventurous women interested in threesomes and those who want the safety of having a trusted third party along with their new bit of strange.