After All These Years by Susan Isaacs
"He was the size of a small Alp. Six feet six. Two hundred and twenty pounds. From Richie all he'd inherited was soulful black eyes, but at least they established his paternity. "Mom." His voice was deep and gentle. "Try to calm down."
Teaser blurb: "Richie Meyers tells his wife Rosie he is leaving her for a younger woman. Then he turns up murdered. Naturally Rosie is the prime suspect. Her only hope lies in uncovering Richie's secret life (and his killer) among the Manhattan jet set."