1. Usually a long-distance relationship where the couple still want to be together, but one or both of them also wants to see other people. Occasionally used to test their partner. Sometimes causes heartbreak, especially when:
A: One person falls for the new person they hooked up with and falls out of love with their long distance partner.
B: When the person in the long distance relationship didn't tell the new person that he/she was already in a long distance relationship before dating said person, i.e cheating.
2. A polyamorous relationship.
1. Girl: "Okay, we gotta talk. I really do love you, and I wanna stay together, but I'm in college now and 100 miles away from you. I still love you, but I want to meet other people while I'm in there. So, let's make this an open relationship, okay?
A: Guy: Ugh, I can't believe I agreed to an open relationship, now she left me for some player!
B: Girl#1: "Man, I can't believe that he actually dumped me for this chick in college!"
Girl#2: "Ouch. Didn't you know? He is in an open relationship with her."
2. Girl#1: I heard that Jack is in an open relationship, isn't that crazy?! He walks around holding two girls hands like he owns them!
Girl#2: Well, hey. At least he's not cheating on them.