I don't understand people being in open relationships where they are not monogamous.  Why even BE in a relationship?
That is a great question.  To me, an "open" relationship sounds more like "no" relationship.  What say you?
I agree.  Open marriage relationship couples report high levels of marital satisfaction.  That is just twisted.
I don't accept that premise.  Do you happen to have the % of stats?  To me, polls or studies such as that are slanted to create "facts".  
No, what I have read just said "many couples."  They don't even know the origin of the term open relationship.  Had to be late 60's.
I agree with you.  "Many" is a subjective term.  Many could be 10.  Marriage itself is a committed and dedicated relationship.  That's the point.  I believe relationships need to be clear, not "open."
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
valued, differences are not seen as a threat.
- Mutual trust: an assumption that everything is out on the open and that one’s partner is not a possession that is guarded.
Relationship maintenance.
The impact of open marriage on relationships varies across couples. Some couples report high levels of marital satisfaction and have long-lasting open marriages.
Other couples drop out of the open marriage lifestyle and return to sexual monogamy. These couples may continue to believe open marriage is a valid way of life,