1. Whether it’s your Bride, Spouse, Date or just someone you are accompanying. If that someone you are with has chosen to dress in a formal, it is fashionably correct to dress at the same level of dress. This is one of the last standing bastions of dress etiquette.
** It’s your special day you call the shots. From that standpoint there is truly no right or wrong way. As long as there is an understanding of what’s the norm and what may be expected.
2. It’s your special day and dressing special will make it even more so. Clothes truly makes the man and nobody really gets compliments like a guy in a tuxedo.
3. Dressing special is both to honor that special someone or to honor your host if you‘re a guest. This is a many times forgotten old world tradition and includes the wearing of suits (semiformal) while attending special occasions.
4. If the invitation says Formal, Black Tie, Black Tie Affair or even Black Tie Optional it normally means that the host has decided anything from, you must be dressed in a formal to it is preferred that you dress formally if it’s not too much of an imposition because that is how the host will be dressed. Semi-Formal means business suit. If you feel the host may not understand the correct terminology, you may want to call to make certain.