Affair

An affair happens when a Sim in love with another Sim interacts romantically with a different Sim.

Getting Caught


Having an affair can be risky as getting caught can possibly ruin the relationship with the other Sim.

Ways a Sim can get caught:


 * WooHooing on the same lot as another lover passes by, even if they're on opposite sides of the lot.
 * Going on a date when the other lover enters the room.
 * A lover sees the flowers a date may have left (though an apparent bug in TS2 means flowers sitting on a shelf or other surface might go unnoticed).
 * A child who sees the adulterers mid-WooHoo may tattle.
 * Sleeping in the same bed when your lover is around.
 * Doing any romantic interaction to another Sim while the lover is around.

When this occurs, the Sim will be slapped and a lot of relationship will be lost.

Interestingly, Sims can be caught cheating by the ghost of a deceased Sim with whom they had a romantic relationship before that Sim died. The ghosts can even become furious with the Sim who cheated on them.

Getting caught by children

If they catch their parents cheating, they get the same relationship decreases, and if left to their own devices, may even attack their own parent or who the parent is having an affair with. They don't get any visible memories from this aside from any meetings, but effectively act like a Sim who has been cheated on. They'll either cry or get angry at the parent. However, if one of their parents had died and they somehow didn't know about it, it could cause needless drama if they consider looking for love again as cheating.

Jealousy
Whenever a Sim, who has a crush or is in love with another Sim and watches the latter partake in some romantic interaction with another, fury occurs. This doesn't take into account whether the feelings are one-sided or not, which may be messy for unrequited crushes. It may even still cause some kind of jealous reaction if the flirting is done by someone else and rejected, though it's not really confirmed.

The witnessing Sim often loses the crush or love marker, and his or her relationship with the cheater and the one he or she's cheating with plummets into the negatives (if he or she doesn't know the other person, a "Met Sim" memory is added along with the affair and possible "Fell Out of Love" memories). In Nightlife, this also triggers fury, and it tends to last quite a while. This relationship drop enables breaking up, assuming the Sims were going steady, engaged, or married.

The cheated on Sim will reject the cheater should they try to interact with them romantically.

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The Sims, The Sims Bustin' Out and The Urbz: Sims in the City
When cheating occurs, the Sim will be slapped and the 2 Sims will lose -50 relationship points.

The Sims 2 and The Sims Stories
As in The Sims and The Urbz, the Sim will be slapped and relationship points will be lost. In Nightlife, Deluxe, Double Deluxe and The Sims Stories, this can also trigger Fury.

The Sims 3 and The Sims Medieval
When affairs/cheating occurs, the Sim will be jealous and some relationship is lost. No points are lost if the No Jealousy is chosen.

With The Sims 3: Generations, when a cheating occurs Romantic reputation may change, and after sometime the spouse/lover may get the "Betrayed" moodlet and will autonomously accuse the Sim of being a cheater and their relationship will decline.

The Sims

 * Using a romantic social such as Kiss when that Sim has a lover. A sound will also be played if cheating occurs
 * Using an Act Romantic social or the Blastikiss Power Social

The Sims 2 and The Sims Stories

 * Using a romantic social such as Kiss when the Sim is married or have a lover.

The Sims 3 and The Sims Medieval

 * Using any Romantic Social if you have a lover or husband/wife. No Jealously LTR prevents this effect.