I think if you make a new one, you should make it multiple-answer... With Rag I initiated it, but with Sean we were both poly when we met, for instance.
Now, if you're only wondering about established, opposite-sex couples who opened up their relationship (without starting that way), that means less people can vote, but you might get results that are more interesting for what you're wondering.
Me: 31F, straight
Seamus: My husband, 32M, straight
Dragon: My boyfriend, 29M, pansexual, married to Fox
Fox: My boyfriend, 29M, homoflexible, married to Dragon