Responses
10 years where i love You the most. Its a manhwa though, and has so much angst ;;;
http://www.mangago.me/read-manga/hina_wa_mitsuiro_no_koi_ni_torawareru/
Not sure if you'd consider it as cheating, but the betrayal part is strong with this one.
manga where seme betrayed uke? like cheated on him or.. u know