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 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
intimacy between coworkers. These connections can be categorized into three different classifications: romantic partnership, sexual partnership, and combination partnership. A similar relationship type that often gets confused with workplace romance is work spouse, but this is an intimate friendship between coworkers rather than the actual marital relationship.
Romantic partnerships involve a strong emotional attachment and close connection between partners without sexual relations. Sexual partnerships are a partnership with a lack of an intimate connection, and instead include a strictly physical and sexual relationship. An example behavior of employees in