You had a choice, floo. No-one has to dress up in a big confection for their wedding though most want to wear something good. A lot of people feel like you and if I had my time over again I'd get married simply, just me and J and two witnesses (you can do that just as easily in church as well as at the Registrar).
However, back to the op: in recent times many women in the public eye have stated that they don't care too much about how they look, dress or whatever; if the paps catch them going out to the newagent in an old shirt, baggy shorts and flipflops, no make up or hair-do, they shrug. They say they have to be comfortable when doing ordinary things and I agree 100%.
Male looks and apparel are criticised nowadays in the way that woman have always had to put up with. A lot of young men spend a tremendous amount of time on their appearance and I don't just mean good clothes but personal grooming. However, everyone is entitled to slob out without comment from others and it pleases me, when it happens, if the object of comment couldn't care less.