Lifestyle guru B. Smith has Alzheimer’s. Her husband has a girlfriend. Her fans aren’t having it.

EAST HAMPTON, N.Y. — It was 10 a.m., and B. Smith was shuffling around her house in socks and leggings and a bright red sweatshirt emblazoned with “Wilhelmina,” the prestigious modeling house to which she once belonged.

She is still model-slim at 69, actually. Her face, now framed with a halo of tight gray curls, is just as it was 20 years ago, when B. Smith was on TV, on the cover of magazines and books, when she had restaurants, when everyone seemed to call her “the black Martha Stewart,” as if it weren’t enough to just be B. Smith.