I'm not going to attend my friend's wedding because her husband will be in military attire
Why do you have a problem with his military attire?
Her husband's clothes are really ugly, I can't stand to look at them.
Not liking her husband's clothes seems a shallow and rude reason to avoid a friend's wedding. It's fine to have negative beliefs about the military, but you shouldn't chose not to attend because you think his clothes are ugly. You will probably lose your friendship if you do.
You are right. What I'm doing is shallow. I will attend the wedding.
Good that you changed your mind. Being there to celebrate with your friend's most special day in her life is what's most important.