1 is "wear a shirt"
2 is "put on a shirt"
-ing seems to be attached to wearing.
So wearing is like a progression form.
It is right in a sense.
but wearing is almost a complement.
"wear" can be used like here.
He wears a mustache.
He wears a shirt.
What is difference between "wears a shirt" and "is wearing a shirt"?
"is wearing a shirt" is temporarily,for a short time but after putting it on.
"wears a shirt" is relatively,for a long time after putting it on.
"put on" is not used after putting on a shirt,it is an action has a finis!
I wear new suits to the party.
(It is not that I am putting on new suits on the way to the party as I get to near the place, as time goes! it means that I put on new suits and go to the party!)
I'm wearing new suits to the party.
It makes no sense.
It means that I wear new suits temporarily, and put it off, and go to the party.
you probably go to the party with naked or under shirts.