I can't find this particular M/s incest story, been looking all over

I remember it begins with the mother/wife being upset that her husband wasn't pleasing her, and her friend tells her she needs to be more assertive, or adventuresome, or something like that. So one morning, when she's half asleep her 'husband' comes up to her in bed to talk to her, and she demands he start fucking her. It's only sometime towards the end, or after the fuck, she realizes she'd mistaken her son for her husband and that he was in the shower. This starts an affair with the son coming in about every morning while the husband is in the shower to fucker his mother.

Those are the most defining aspects I can recall. Hopefully some of y'all can help. The story was multi-chapter, and incomplete, but I don't recall if it was current or old.