My brother says he would rather keep an open relatioship prior to his wedding.open relationship is an intimate relationship which is consensually 
That's cool,so why doing that?
it is often used to signify a primary emotional and intimate relationship between two partners who agree to have sexual relationships but not romantic relationships with other people
Wow! That's like sticking to each other like glue I suppose.But how could one of the partners in the relationship determine that?
Open relationships include any type of romantic relationship
So when was it recognized ,to be anything serious?
of open relationships.
To a large degree, open relationships are a generalization of the concept of a relationship beyond monogamous relationships. A form of open relationship is the open marriage, in which the participants in a marriage have an open relationship.
There are several different styles of open relationships. Some examples include:
- Multi-partner relationships, between three or more partners where a sexual relationship does not occur between all of the parties involved.
- Hybrid relationships, when one partner is nonmonogamous and the other
Open relationship
An open relationship, also known as non-exclusive relationship, is an intimate relationship that is sexually non-monogamous. The term may refer to polyamory, but generally indicates a relationship where there is a primary emotional and intimate relationship between two partners, who agree to at least the possibility of intimacy with other people.
Open relationships include any type of romantic relationship (dating, marriage, etc.) that is open. The concept of an open relationship has been recognized since the 1970s.
Types