Stories where wife/girlfriend is convinced to have sex training so she can be better at it for her husband/bf?

[mrem4n]

I'm looking for stories where a clueless woman is convinced that practicing sex with someone isn't cheating and their BF/husband is blissfully unaware

 

[lifeis2short2b]

Is the woman clueless or the "blissfully unaware husband" the clueless one ?