A relationship expert has warned of the tell-tale signs that indicate a couple is heading for divorce - and says "they're more common than you think". Clinical psychologist Dr. Kathy Nickerson revealed four common relationship issues which reveal a couple will split - drawing on the work of psychologist and renowned marriage researcher Dr John Gottman. Gottman penned the 'Four Horsemen' - four indicators a marriage is heading for divorce. They are criticism, contempt, defensiveness and stonewalling - and Dr Kathy says they shouldn't be ignored if you want your relationship to last. Dr Kathy, from Orange County, California, US, said: "Did you know that there are four behaviours, that if you do them in your relationship, they predict breakup or divorce at the rate of over 90%? It's true. "The research done to find these four behaviours was done by Dr John Gottman of the Gottman Institute at the Seattle Love Lab. "If you've never heard of him, he's a giant in the field of relationship psychology and he's amazing." Dr Kathy explained how the behaviours contributes to a marriage breakdown. She said: "Criticism occurs when you make harsh judgments about your partner's thoughts, feelings, character, appearance, and behaviour. "An example of criticism is 'Oh, so you're just going to sit on the couch today again, huh? You are such a lazy person, you never do anything to help, you're such a blob.'"