I really don´t get the act of cheating on your partner, if you´re already jaded with your spouse, just get a divorce, it will end in the same thing if you are discovered, with the first option the both of you would at least keep a friendly rupture, maybe when the other one gets sick of you, there´s the posibility of returning with your ex. Be it fictional or in real life cheating it´s just as trashy as "them".
"Now, to the dude in the manga" -At least have some dignity and take the fault with "grace"