Nowadays, affairs are common in any Soap Opera and turn up an awful lot in other types of story as well.We don't really a fictional husband and wife to stay faithful to each other for forty or so years.Unfortunately, adultery is Truth in Television, as many broken hearts and broken families will testify.It is also one of the most common reasons that people murder each other. This is generally the #7 scenario of Triang Relations.A few rules usually hold true in fiction: If a woman cheats, her paramour just scored a victory over her cuckolded husband, who is now permanently dishonored.The (male) big boss of any given workplace is likely to be two-timing his wife.Most examples of cheating in shows aimed at adults, however, will involve sex.Occasionally, characters may clash specifically because they have different definitions of cheating: for example, the husband who protests that he was drunk and it was "just a kiss" to his furious wife, or a girlfriend who can't understand why her boyfriend doesn't like her flirting with her male friends.
Something always goes wrong, or at least it should, because triangles usually end up hurting people more than anything else.The Protagonist remains sympathetic if they cheat, and becomes an innocent, wronged victim if they are the one being cheated on.Bisexuals are portrayed as incapable of faithfulness or have merely informed sexuality, and men are more prone to having affairs than women (and often portrayed as The Unfair Sex too when it comes to cheating).However, it's worth noting that even further back in the day, the gods, goddesses and minor side characters of mythology listed "infidelity" under "Hobbies", didn't particularly care if their new "partner" was willing, and got away with it.
Only their mortal lovers got the nasty side of the wronged wife's/husband's temper when the affair was discovered.
Or maybe his marriage is perfectly healthy, and Bob has no excuse.