Fisher has suggested that relationships frequently break up after about four years because that's about how long it takes to raise a child through infancy Passion, that wild feeling, turns out to be practical after all. A couple not only needs to bring a child into this world; they also need a bond that continues long enough to raise a helpless human infant. Maintaining Love Eventually, all couples find that their passion declines over time. For relationships that get beyond the initial stage of passion to have a real chance of lasting, a chemical called oxytocin may be the key. Oxytocin is a hormone our body produces that promotes mutual feelings of connection and bonding It is produced when we hug our long-term husbands and wives or our children. In long term relationships that work, oxytocin is believed to be abundant in both partners sure According to Helen Fisher, couples who want their relationships to last should make an effort to keep a close physical relationship. Through frequent physical contact, they can trigger the production of more oxytocin and in this way feel closer to each other