If I were to approach this project as I would a woman, first I would disarm the reader with sensuality, with eroticism building at a natural pace as if they were stolen kisses, which become harder, deeper, and increase in urgency as the excitement mounts. I specialize in stories where the wife "shouldn't be feeling this way for someone who is not her husband".
I like to explore the thoughts of a highly sexual woman who is reluctantly seduced into infidelity, exploring her initial hesitation as she is thrown onto the bed, her breath quickening and becoming more ragged as hands work their way down her body and expose her sweetest of spots. I like to capture the exact moments when such a woman would give into the sheer seduction, from a moan unintentionally escaping her perfectly painted red lips as she is being orally pleasured, or her being unable to fight the pleasure a second longer, and wrapping her seducer in a tight embrace with her arms and legs, kissing him (or her!) deeply as she meets them thrust for thrust, absolutely needing them to be deeper inside of her.