Why Does Husband Wear Bra?

Probably because you husband likes the look and feel.  I have small breast (fill a B cup) and I wear a bra because it offers support (minimizes the bounce), hides my nipples which other wise show through my clothes.  My wife was the first one to suggest that I really should wear a bra.  She got me to try it and she was right.  So yes I wear a bra daily ... I like the look and feel of it and she likes the look too.

Many men have some chest development, whether muscle, fat or glandular tissue (gynecomastia). Weight gain  and advancing years can create support problems, with sagging or bouncing. Men may be reluctant to turn to the solutions women use, such as a sports bra. They want the equivalent of a sports bra for men.

Ooh!  You've got a cross dresser on your hands.  There's nothing wrong in what your husband is doing, so let him be.  At least he's doing it with YOUR bra and not with another woman's.  Try to play with him when he's in the mood.  Dress him up, apply makeup, let him prance around.  You'll get him SO ready to give you good sex.

He may be getting sexual pleasure from wearing women's under clothing.  Does he wear panties, too?

I have gynecomastia and wearing a bra helps.  I wasn't so happy with the idea of wearing a bra but I thought I would try one because my breasts were  getting so big.  I haven't looked back.  I have been wearing a bra for 3 years now.  My breasts don't ache and back and neck pain have disappeared.