When Mike first told me that he was a naturist, I was suprised, but I was also interested. It is also important to affirm your spouses importance in your life. The Naturist Society is a great resource that can educate you and your mate together. I have gone in the past. While my partner accepts my choices, he is reluctant to accompany me.
Naturist places are clothing optional.
Just because your partner does not want to go nude does not mean they cannot accompany you. If he feels uncomfortable about the way he looks, he will probably find that nude beaches don't live up to the stereotypical perfect body ideal that many folks have. The great thing is that after a few minutes, you forget that everyone around you is nude. It is unlikely you will end up getting one, because you will be enjoying the sunshine and comfort of the beach. If you do get an erection, you should lay on your stomach or sit with a towel over your lap until the erection goes away.