I am at home with my boyfriend. I only wore a bra and underwear, and he was dressed very formally. Is this good?

What you and your boyfriend wear at home is your business, as long as your boyfriend doesn't say anything.

Personally, although it is in your own home, it is not very elegant to wear only bras and underwear in broad daylight.

Personal opinions are for reference only, and outsiders have no right to interfere in your private affairs.