I love rings (and all sorts of pretty jewelry!) so I wear my wedding/engagement ring all the time.
DH is a mechanic and cannot wear his ring to work at all. Since he can be pretty forgetful, it's safest for him to leave his ring in a safe spot and only put it on for special occasions. If he took it on and off every day, I guarantee he would lose it within a week.
Honestly he's gone months without wearing it and it doesn't bother me at all. He and I are both aware of the commitment we have to each other, and neither one of us feels that the other 'has' to wear a ring. I wear mine because I want to. He doesn't wear his because it's impractical.
I actually don't think it's fair that women get engagement rings and men get nothing, so when we got engaged I bought DH an engagement watch. I got his input on styles that he liked, but picked it out myself. The night he proposed, I knew it was coming, so I brought the watch with me and gave it to him after he proposed and gave me my ring.
I don't think it's a big deal that William isn't going to wear a ring. It's not anybody else's business.