We feel differently based on the sex of the person our partner cheats with.
For a 2015 study, published in the journal Personal Relationships, men and women read about hypothetical scenarios in which their partner had sex with someone of a different sex or the same sex. When researchers asked participants how they would feel about it, the men were more likely to be angry and more inclined to end a relationship if their partner cheated with someone of a different sex. But they were more likely to be aroused if their partner cheated with someone of the same sex.
