Go ahead and go, nobody will notice your little dick, everbody will be looking at your wife.
Wait until you hit the beach the first time, and see all the hot women. I got an erection watching the girls play volleyball. Embarrassing, plus my GF still teases me about it.
You will enjoy it. It will be uncomfortable when your hot wife is naked talking to a guy whose dick is twice the size of yours and getting erect, you will probably shrink up right then to their amusement. but you will get really hard when talking to other hot women which they will like, maybe make your wife jealous
Spent three weeks on vacation in Europe on a nude beach and it was great !! You will forget your are nude until you are talking to another woman and she is checking out your cock !! You will feel totally free !!! You will both be totally arouse and you will fuck like bunnies at night ;)