I think I would sit down and have a conversation with him. I would let him know about my concerns and ask him where he is coming from. I would let him know that it is his decision but that you needed to voice your various concerns. Be open minded, ask him for the same. See what comes of that conversation.
In the mean time I would think about what you are worried about. Is it his health, will you not find him attractive? Decide what you can live with and be very honest with yourself. Remember to pick your battles. If this isn't that big of a deal to you and you are comfortable after his explanations, then let it go. Also get out all of your concerns in one shot. Wouldn't be cool to be okay with it and then later decide to have a fit about it.
Hubby and I have been together for over 30 years. He only asked me for one thing after all these years. To not get my nose pierced. He didn't demand or tell me what to do. He just said he didn't like it, but would support my decision. I didn't do it. Because he never had voiced any dislike about anything else, I gave him that one.