In 20 Most Common Mistakes of the Unfaithful Spouse, this statement was made, "The "Break-up, Make-up" cycle is a natural part of an affair." What is meant by that?

My husband had an emotional affair with a woman at work. He broke things off with her almost two years ago and they no longer have personal contact but do have times when they have to be at the same meetings and are included in the same office emails. There is "bad blood" between them now, as it has become evident that she is spreading falsehoods about him personally and the nature of their relationship they had. If my husband remains with the company, what is the possibility that they could repair the breach and get back to a more intimate status again?