I'd like one ring to rule them all... but he wants 3.

I have been looking for rings lately. A wedding band for him, and a more proper engagement ring for me. We need to at least get the engagement ring before I move away. So I brought it up to the Mr. yesterday. Apparently he has a few preconceived ideas about the rings that he failed to tell me previously. I don't have a problem with him having his own wants and needs, I actually welcome that. But he's terrible at explaining, and I can't figure out why he wants what he wants. We've made an appointment with each other to choose rings on Friday, but I'm still not sure I understand. Are there specific things that are supposed to happen with rings? What if I don't want to wear more than one ring? I've actually mentioned this to him before. Why should we spend money on an engagement ring that's going to be put away in a box as soon as we're married for the rest of eternity? He wants our wedding bands to match, what If I don't want the same ring he wants? He also says that I can't use my engagement ring as a wedding band as well. He specifically said that. The wedding band must be the ring that he puts on my finger the day of the wedding, and not something I had been wearing before. I'm not completely opposed to the idea of matching rings, and could consider the others... I just don't understand why, all of a sudden, he has these opinions about what's right and wrong procedure for rings. Is there specific protocol that I'm missing, something that I should consider? Sometimes I wish he had a longer attention span.