When couples add an extra person into their relationship, it is referred to as a triad or polyamorous relationship. This type of relationship requires a lot of commitment and trust between all of the individuals involved. Couples must be willing to communicate openly and honestly, as well as support each other. There can be unique challenges and sacrifices made in order to maintain balance and fairness, but many triad relationships can be successful. Every relationship is different, so couples must figure out what works best for them.