For some Abrahamic religions (I am not sure about Christianity), being clean and being pure are distinct concepts. There are cases when one can be pure, but unclean/dirty and vice versa; having sex fluids on you is a case of being both (depending on your hygiene preferences). If it's just you or partners fluids, then one may not count that towards unclean, but it wouldn't be "clean" for a religious thingy.