In human chemistry, Gottman stability ratio is ratio the the exchanges of positive-to-negative interactions in a relationship, in which stable long-term marriages have a 5-to-1 ratio of attraction to repulsion in the exchange force of their bond.  The term is named after American mathematical psychologist John Gottman, who discovered the dynamic ratio in the 1970s after video recording the interactions of several hundred married couples and then later keeping track of divorce patterns years later. 
● Müller stability ratio
1. (a) Thims, Libb. (2007). Human Chemistry (Volume One), (preview), (Section: “Gottman stability ratios”, pgs. 179-182). Morrisville, NC: LuLu.
(b) Thims, Libb. (2008). The Human Molecule, (preview), (pg. 46). Morrisville, NC: LuLu.
2. (a) Gottman, John. (1994). Why Marriages Succeed or Fail. New York: Fireside.
(b) Gottman, John M., Murray, James D., Swanson, Catherine, Tyson, Rebecca, and Swanson, Kristin R. (2005). The Mathematics of Marriage: Dynamic Nonlinear Models. MIT Press.
● Gottman, John. (2007). “The Magic Relationship Ratio” (Ѻ), Mar 13.
● Stable marriage problem – Wikipedia.