Gamous or gamic is that particle at the end of monogamous, poligamous, bigamic, etc. It means marriage. Modern day romantic/sexual relationships are basically proto-marriages, even the so called polygamous ones, but sexual exclusivity and such excessively contractual relationships will tend to generate problems.
The idea is to avoid the concept of "couple" or partner and instead try to form relationships more gradually without the discontinuity or sudden jump in relational status that establishing a couple implies. The sudden increase in intimacy and expectations is almost never justified in a true mutual understanding but rather in mutual idealization i.e. fantasy. Living in such illusion tends to generate problems and such relationships tend to end after at most a few years nowdays, leaving people with a precarious social landscape since they spend all their energy and resources in ther partners.