The best way to get over a break-up
In 1949, Hank Williams put into a famous song about how it’s hard to get off our mind the loss of a close relationship: “I can’t get you off my mine, when I try I’m just wasting my time. Lord I’ve tried and I’ve tried, and all night long I’ve cried – but I can’t get you off my mind.” [1]
Many clinical psychologists have affirmed this in their research:[2] Suppress thoughts[3] of a no-longer desired relationship (old flame) and you will be inclined to think more about it afterward.[4]

Explanations from these researches may be simplified into the following propositions:
1. Suppressed thoughts come to your conscious mind when you are concentrating upon something else.[5] The unwanted thought will continue in your consciousness even when you stop suppressing it.[6] That also happens to the suppressed emotional thoughts of a lost love (old flame). [7]  This happens because the verythought-suppression process brings up past bodily sensations, emotional thoughts and experienced emotions with the old flame. The suppression itself invokessadness and when the suppressed thought later returns, that sadness returns as well.[8]
   2. Suppressed thoughts return unbidden and without any apparent connection to some ongoing train of thought. They create ‘greater emotional disturbance than thoughts that are purposefully invited to mind or that follow from an intentional train of thought.” [9]
    3. However, there is a difference between remembering an old flame who is still desired (a hot old flame) and one who is no longer desired (a cold old flame). In the case of a cold old flame, suppression creates a later tendency to dwell on thoughts of the old flame.[10] For a hot old flame, suppression creates an intense emotional response in the conscious mind. It may be manifested in just a feeling of sadness. There is no desire to talk about the old flame, possibly because "such thoughts are naturally suppressed and these people have become too good at suppressing their unwanted thoughts".[11] Another possible explanation is that "the suppression of an emotional thought produces a desire to continue suppressing the conscious thought".[12] For example, one participant said, “I am not saying anything about him because I don’t really feel like crying and if I keep talking about him I might shed a tear or two.”
    4.   A study showed that talking about the cold old flame reflects a lesser desire to honeymoon the old flame. This suggests talking about the old flame leads to a drop in interest in the cold old flame. In other words, instead of burying your thoughts about that old flame under the carpet, just blab it out. Better still, if you are a man, you can be a candidate in the popular reality dating TV program called "If You Are the One"  Fei Cheng Wu Rao 非诚勿扰. It gives you a fantastic change to 
cry it out loud
*:(( crying to an audience of some 50 million people many of whom will empathise with you. If you get lucky, you may even walk away with a highly prized replacement amongst the 24 beautiful women of modern China.  

[To be continued with suggestions on how to stop thinking about an old flame]

A more modern version is by Johnny Bush which sounds better acoustically: An original Hank Williams’ version is from his show in 1949: 
[2] See eg: Horowitz, 1976; Janoff-Bulman & Timko, 1987; Pennebaker, 1988.
[3] Wegner, D. M. (1989). White bears and other unwanted thoughts: Suppression, obsession, and the psychology of mental control. New York: Viking/Penguin. German translation by Ernst Kabel Verlag, 1992. 1994 Edition, New York: Guilford Press. 
[4]  Wegner, D. M., & Gold, D. B. (1995). Fanning old flames: Emotional and cognitive effects of suppressing thoughts of a past relationship. Journal of Personality and Social Psychology, 68, 782-79; [NOTE: When you place your computer/house cursor on the  icon, it links you to the article immediately. Try it]. ; Lehman DR, et al, “Long Term effects of losing a spouse in a motor vehicle crash’, 1987 Jo of Personality and Social Psychology 52, 218-231; Lindemann E, ‘Symptomatology and management of acute grief’, 1944 American Jo of Psychiatry 101, 141-148; Pennebaker & O’Heeron, 1984; Tait & Silver, 1989.
[5]  Wegner & Erber,  1992, They hyperaccessiblity of suppressed thoughts, Jo of personality & Social psychology, 63, 903-912; Wegner, Erber & Zanakos, 1993, Ironic processes in the mental control of mood and mood-related thought, Jo of Personality and Social Psychology, 65, 1093-1104
[6] Martin, et al, 1993, Wanting but not having: The effects of unattained goals on thoughts and feelings, in Wegner DR, (ed) Handbook of Mental Control, pp 552-572,
[8] Wenzlaff, Wegner & Roper, 1988, Depresion and mental control: The resurgence of unwanted negative thoughts, Jo Personality & Social Psychology, 55, 882-892.
[9] Marcel Proust calls this the Law of Intermittence: “Emotion-laden stimuli that leave one cold when sought out or turned to in thought may move strongly when stumbled upon”: Frijda, 1986, pp 427-8.
[10] This is the suppression-induced rebound effect found in Wegner, et al, 1987.

[11] ; see also, Wegner, 1994a.Ironic processes of mental control, Psychological Review, 101, 34-52; Kelly & Kahn, 1994, Effects of suppression of personal intrusive thoughts, Jo Personality & Social Psychology, 66, 999-1006;