Why did my husband get denied by a sales manager after being approved for a home loan because the sales manager was upset with his wife.

Businesses have no general duty to extend credit to anyone. They may refuse credit to a customer whom they do not like, or who wears the wrong color socks, or who annoys them. It is impossible to answer your "why" question, but the facts that you inquire about do not suggest any legally cognizable misconduct by the lender.