Lara and Larry have a baby, Klaude. Lara then leaves Larry and marries Jeff. With Jeff she has many more babies, one of them named Faye. But Larry goes and has a kid with Lucy, Garrott. What is Garrott to Faye... I know Garrott and Klaude are half-brothers.
There is no such designation as half siblings by marriage. You are either related or not related and they are not.