However, Matysa PuranaMatysa Purana doesn't consider this as incest. But we should consider Vedas or Sruti as infallible truths over other scriptures. (I will update this answer for Brahma once OP provides details about Brahma story).
Vishnu was cursed by Tulasi to get seperated from His wife and demons would kidnap His wife (alluding to Rama Avatar). But Parvathi askedasked Her brother Vishnu to defile Vrnda only when Jalandhara went to Parvati in disguise as Lord Shiva.
Also, Jalandhara just wanted to take revengewanted to take revenge on Devas since Devas acquired gems and pearls during churning of ocean. But Indra had his reason for stealing gems since Ocean God hid mountains in him when Indra was cutting their wings. This is because mountains were disturbing yagnas and killing people when landing.
This is what vrinda cursed Lord Vishnucursed Lord Vishnu for defiling her chastity as a part of Shiva's mission.
Wives of sages were attracted to Him and sages cursed Him. This is how Chapter 29Chapter 29 of Linga Purana describes this incident.
The sages spoke harsh words to Rudra and cursed Him. Later Shiva Himself explained the Darukavana sages subtle and esoteric significance behind His Digambara appearance in Chapter 34Chapter 34 of Linga Purana.