Obviously, this sort of thing is controversial since many fantasies, if acted out, violate church standards and plenty of church counsel has been against allowing ourselves to actively think about such things. That said, I think there's benefit in exploring fantasies of all kinds AND sharing those with spouses, even when the fantasies center around things we wouldn't choose to do, either because of covenants or a sense that it wouldn't be as enjoyable in real life as it is in our imagination. I think so because our fantasies simply reveal our authentic erotic natures. We can't exactly choose what turns us on the way we can choose what we'll allow ourselves to actually do. Our turn-on's, including the hardest to talk about, are part of who we are. We need not be ashamed of it but isolation helps to ensure we feel that shame anyway. Being able to disclose these authentic thoughts and feelings to an understanding spouse can be a powerful bonding and healing experience.