In my opinion, open marriage is both a good and a bad idea. Good because, the spouse does not get to cheat on the other as he or she is aware. However, it is bad because I believe when you settle for a marriage, you should be sure of who you want and avoid all the others.
(This is my opinion) I don't think its a good idea and the person(s) should be sure on who they really want to marry. Because Ive seen some people who are in an open relationship and the people/kids have lots of tension.BUT its not up to me and people should (if they want) be able to have an open marriage if its what their heart wants and if they think its good for them.