My wife and i have discussed this issue, and we do tell each other everything= as our relationship has grown i have seen how deep we have become with each other, there are times when we tell the other a fantasy and state that it is a fantasy and there are other times when we have both developed the others fantasy so we can both get off from it, whilst there must be something that perhaps we haven't shared i have seen that to be 100% has been the best for us, and it is just between us.