Is it something you knew you wanted before the relationship started or did it become something of interest in the middle of the relationship to save it?
With my second husband, we knew each other in the lifestyle before we got together romantically. My first husband and I also knew before we were married that we were going to have an open relationship.
Usually as the relationship started. One time it occurred shortly, a few weeks, after we became a couple. In my first LS relationship the woman quickly seduced me into it. Later I introduced a couple of college student gf into group sex, couples swapping, and bisexuality. When dating the conversation about her sexual history and interests would lead to the subject of exploring groups sex and swinging. Thesedays I meet sexually open women in internet based swinger venues, so there has always been a assumption at the start of sharing the LS however long we dated.
It just naturally evolved for us. We met in a club that catered to the bi/gay/les lifestyle. After having a wild weekend romp together, we basically knew that we were both bi, so we talked it out BEFORE she became even my girlfriend. By the end of the talk, she was my girl. We allowed each other to do our same sex thing. It was individual at first. Then one year there were like 5 new hires at her place of work, all sexy, hot bi women and things began to escalate very fast almost immediately. It started out being threesomes, then one night, at our house, 2 of the women were there with their hubbies and a drunken orgy broke out in the living room. After that, it was on!
My boyfriend knew at the outset that I was bisexual, and had no intention of giving up sex with other women for him. After a couple years of sharing me with my girlfriends, he realized that I was committed to spending my life with him, and any fears of losing me to other sexual partners were unfounded. He began fantasizing about sharing me with other guys too, and I was open to the idea, so we tried it, and found that that worked too. Then I started feeling guilty because I was the one having all the fun, so I suggested we try swinging as a couple, and partner-swapping with other couples. That lasted for almost 3 years, until I found a girl I fell in love with. That began our polyamorous period, (FFM) and I shared her with him for several years, and we gave up swinging with other couples. After a few years, my girlfriend went away to grad school, and it became difficult to maintain a long-distance relationship. I started fucking other guys again because my boyfriend really got off on how much other guys wanted his girlfriend, and he enjoyed having the power of deciding who got to have me (of course, I got a say in the matter too, but we usually agreed). By this time, I was in my early 30s, and my relationship with my girlfriend had fallen apart, so we decided to move one of my boytoys in with us while he was going to college, and he became my defacto 2nd boyfriend, and we were once again in a polyamorous relationship, (MFM) where we stand today, only we've brought one other couple, and a couple more younger guys into our group of FWBs, and there are 5 guys and 2 girls in our circle currently. But I live with my two boyfriends, and the others just come over for sex whenever it's convenient. This has been the situation for the past 5 years, and looks to be a pretty stable arrangement. (There'll be a quiz later! LOL)
Our's developed after 23 years together when my wife expressed she was bi-curious but she didn't want to go with another woman alone at first.
We started with a three-some with her friend and did just the two-women threesomes. After a while that developed into other couples as well.