I'm not sure that
cheating is OP's concern, per se (feel free to correct me, OP). I'm thinking that maybe she's uncomfortable with DH being the target of so much female attention that could lead to sexual tension, not necessarily temptation. Based on many of the comments I've read throughout DCUM it seems to me that women (and I say women because they are the ones who seem to comment the most) are just as concerned about a man's guilty
mind as his body. Maybe even more so. "He can look, just not touch." Eh, not so much I think.
I think it's realistic to be jealous, OP. They will be picturing him naked, and he will probably do the same. But with any luck you'll be having some of the best sex of your life.