Netoraretemo Anata no Kanojo.

His tongue against mine... Fingers relentlessly, yet gently assaulting my wet secret place... Why am I reacting to the touch of a man other than my boyfriend...?

(Source: Coolmic)

Volume 1: Netoraretemo Anata no Kanojo. (寝取られてもアナタのカノジョ。)
Volume 2: Netoraretemo Anata no Kanojo.: Ibitsu na Koibito-tachi (寝取られてもアナタのカノジョ。～歪な恋人たち～)

Notes:
- Includes 2 extra chapters.
- Originally serialized as a web manga under the title Maihama Yuuki no Iki-gao wa Bukatsu Komon no Ore shika Shiranai (舞浜有希のイキ顔は部活顧問の俺しか知らない).
- Simultaneously released in long-strip and traditional formats.