OkCupid, among the biggest main-steam dating platforms, is including an element particularly tailored to non-monogamous people
The function allows two users, placed in a relationship status as “seeing someone,” “married,” or in a “open relationship,” to connect their pages together. (This will probably just take place if both users agree.)
Formerly, partners trying to relate to a person that is additional one profile, and had been hence restricted to including just one person’s characteristics: gender, ethnicity, height, etc.