"David afterward married Abigail. He was already the husband of one wife, but the custom of the nations of his time had perverted his judgment and influenced his actions. Even great and good men have erred in following the practices of the world. The bitter result of marrying many wives was sorely felt throughout all the life of David. PP 668.1"
"Neither shall he multiply wives to himself, that his heart turn not away: neither shall he greatly multiply to himself silver and gold."
EGW directly addresses David's multiple wives and connects it to the principle in Deuteronomy 17:17 against multiplying wives, arguing that it led to negative consequences. The connection is clear and intentional.