We had been together about a year. The start of our relationship was an open-minded FWB deal where we explored our kinks with one another. Boundaries were pushed. Boundaries were crossed. We ended up growing close and deeply involved. The entire time, however, we had remained exclusive.
Here and there talk would spring up about past experiences and desires if more partners. Being both openly bi-sexual, we talked freely about both genders attractiveness and being "free" so to speak. Nothing was pursued actively though. It remained a fantasy.