there are so many different types and purposes for collars its amazing boo
i honestly fail to see how you disrespect anyone for keeping it if you want
the collar like a ring, or an ankelette or tatto etc, is just a symbol, it has no more meaning than that which you give it
as for telling him, why not show him whatever it was that convinced you to begin with , let him see for himself, and make his own dicission, if its not something for you two than its not, communication is key, speak or write how you feel to him
for me the greatest collar i wear is in my heart