When does extramarital friendship cross the line over to infidelity? According to You May Call it Cheating But We Don’t, it’s fine to veer once in a while from the relationship straight and narrow. This first-person true story raises a whole set of related questions: Is kissing enough to change a friendship into an affair? Should the partner be told about this? If the kissing progresses farther, at what point is the affair likely to threaten each person’s marriage or primary relationship. According to author Amy Calhoun, it’s fine to kiss a friend without putting the marriage in jeopardy. It’s fine to kiss a few people. In fact, attraction to other people seemed to her to be a normal aspect of marriage, even happy marriages.