1. Tonari no Oji-san
The husband in this story is a bit of a clutz and has a super erotic bod.
So much that the university student living next door cannot keep his eyes off him.

One day, the student gets a foot in the door when invited to eat together after helping the husband out...
After several "lucky pervert" accidents, the university student finally crosses the line and makes a move.

...And the husband is washed away by the pleasure sent through his nipples...

[University Seme x Married with Children Husband Uke]

Official Translations:
English, S.Chinese, T.Chinese, Korean

2. Zoku Tonari no Oji-san
In this volume, the situation / setting is that the married man's wife is in the bath.

Official Translations:
English, S.Chinese, T.Chinese, Korean