Instead of marriage by law, Alpha/Omega tie each other physically through bonding where they exchange pheromones to mark their partner. Bonded Alpha/Omega are called mates instead of husband/wife. Mated Alpha/Omega will undergo psychological and physical change as a result of the bond such as not being enticed with other gender's pheromones hence are immune to other people's mating calls (heat or seductive emission) and being extra trusting of the other. Other single Alphas/Omegas will also no longer find mates ones attractive due to the presence of the other's mate's scent which mixed together during bonding. For Omegas, they will naturally want to obey their mate while Alphas tend to be extra protective over their mate's safety especially during heat and pregnancy.
Bond is done by biting the lower neck of the other which allow them to exchange their pheromones and is usually done by the alphas due their strength making the biting process easier and quick. Bonding partner can reject the bond by refusing to exchange theirs, but bonding process is usually physically intense, so rejection almost never happens. This led to problem of forced-mating where rutting alphas unconsciously bite the omegas during sexual intercourse or even intentionally bite the other - an act which is now considered a crime.
Bonds can be broken by separating the couple until the bond weaken and eventually breaks. This process usually takes about a year and is very stressful to both the Alphas and Omegas as they are emotionally and psychologically attached to the other. Physical reaction from the separation can be described as similar to withdrawal syndrome and mated Alpha/Omega are very attached to each other experience which is why if a couple needs to be separated due to reasons such as abuse, authorities will get involved. Unfortunately, they also experience the same effect from their mate's death, or when apart from their mates for a certain period of time due to unavoidable reasons.
Betas cannot undergo bonding process due to their lack of pheromone glands such as the other two. When an Alpha or Omega choose to be with a Beta instead they will do so through marriage. In this case, the Alpha/Omega will not go through the emotional and physical changes and will still be susceptible to the opposite secondary gender's effects (heats, attraction, etc).