Silsilah as-Sahihah 1493 — Spending three or seven nights with second

Sayyiduna Anas (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "When a man marries a virgin woman while already having a widow (or divorced woman), he should stay with her for seven days; and if he marries a widow while already having a virgin, he should stay with her for three days."