I only ask because I was sort of similar when I got married and I wasn't planning to wear a 'weddingy' wedding dress. I went and tried some ball gowns on and was going to do that. Then my lovely Mum and Sister took me to try on some dresses (not to buy one) and I was amazed at how different I felt, how 'right' the right dress felt.
If the dress makes you feel fabulous go for it though, because that's what matters.
You wouldn't run your decision past him if you went in a bridal shop and picked a new dress, so no need to tell him about the dress you already have. Don't mention it, he won't ask where you got it from.
I'm a second time bride and we're planning a happy family orientated day with lots of friends and lots of kids. It's not until summer 2014 and we are saving like mad and I'm slimming like mad. I've been looking at dresses and although I know I'll be slimmer by then there's just nothing that strikes me particulalry and those I do like the look of are mad money. I do have an ivory evening dress which I wore once to a ball with my exH about 15 yeasr ago which would be almost perfect (once I've slimmed down). OH has never seen it before. Would it be wrong to use it without telling him? he went when I suggested using a ring my Aunt had left me as an engagement ring as he wanted me to have a new one.