Normalization

Relationship between a husband and wife could be said to be not normal, because unlike all other relationships in a family, it entails not just responsibilities and support, but also expectations of stigmatization of any romantic relationships with others, which prevents from free exploration and engagement with among the most complex objects in universe -- other people's minds. This stigmatization can be a factor stopping other (especially married) people from freely engaging in that exploration.

Normalization would work as follows -- once the romantic relationship with the married person has subsided, married people could declare themselves normalized, which would make them simply family members, without expectations any others than those from family members (e.g., like brotherhood).

Ordinary family members don't expect you to spend your time together just with them, that you don't have a girlfriend or boyfriend, that you can't fall in love with someone. On the contrary, normal family members encourage it.

Normalization would entail the relationship has become normal, and society would have to treat the couple as in family, without applying the norms other than those for normal family members.

This would work well with law as well, since people would not have to divorce, so, they would not have to lose any marital benefits they might have.

So, normalization could adjust social expectations.