My Partner's Cheating Means I was Bad

It's easy to blame yourself when something goes wrong. But the simple truth is that the majority of people do NOT cheat - whether it's in marriage or anything else. The majority of students in school don't copy off their friends' papers. The majority of people in the workplace do not run off with computers. Your partner knew it was wrong to cheat. If he/she had a problem or issue, that mouth exists for speaking up and saying something. If your partner chose instead to actively engage in intimate acts with someone else, that was a bad choice, period.

Every one of us is a human being with free will. Jealousy and temptation have existed for thousands of years. Millions of people have resisted those temptations. If your partner failed, that is your partner's failing.