A relationship breakup, often referred to simply as a breakup, is the termination of an intimate relationship by any means other than death. The act is commonly termed “dumping [someone]” in slang when it is initiated by one partner. The term is less likely to be applied to a married couple, where a breakup is typically called a separation or divorce. When a couple engaged to be married breaks up, it is typically called a “broken engagement”.
Cycle of a breakup:
Steve Duck outlines a six-stage cycle of relationship breakup, including
Dissatisfaction with the relationship
Discussion of the reasons for the discontentment
Tidying up the memories
Recreating sense of one’s own social value