Not sure if this Saho from State of a Certain Wife. On the one hand, she has the mole in the same spot so this might be a flashback/prequel version of her. On the other hand the image wasn't included in the series pool on pixiv.

She's the same character. Her nickname here is Sappon, and the title indicates she's "the wife". Author probably just wanted to isolate the prequel so he could do both in parallel.