I am in one (I think... see below). We agreed to open the relationship, IDK, 7 years ago? Something like that. We're both bi/pan, and sexuality- and kinkwise pretty incompatible. Neither of us was remotely willing to give up the relationship because of that though, because romantically and non-sexual-intimacy wise, the relationship is amazing. Oh god I love her so much.
Anyways, we decided to open the relationship with a couple ground rules:
- Always communicate. That includes informing the other person before one goes on a date, for example.
- Sex only. We aren't poly, and are both not ok with the idea of romantic connections forming... Romantically monogamous, sexually open, I guess.
- Protection, duh.
She went on a couple of dates but didn't actually end up sleeping with anyone, I slept with a couple of people. And... things were cool! It worked out for us. If anything, we grew even closer.
The reason I said above that I "think" we're in an open relationship is simply because neither of us has taken advantage of the openness of the relationship in at least 3 years, lmao. And so if I would decide that I'd like to get active again in that regard, that would 100% be preceded with a "hey, are we still open? Are you still comfortable with that, or have your thoughts changed?" conversation.