The good news is, navy and dark blue is in this season
Looks like your summer dress will work for a fall event!
Now, if the blue is a NAVY BLUE, I would definitely go with the brown suede. But if it's a dark blue, I really see nothing wrong with wearing black boots with it. In fact, a lot of garments out there are color-blocked that way. The only thing I would do is add a skinny black belt at your natural waistline (over the dress, of course) and you should be okay with the black boots.
I think you should go for whatever makes you comfortable! No matter what your husband says, you'll be happier if you get to wear what you want
I hope you have a fun time this weekend!