This was originally published at the girl-power site Off Our Chests. The comments on the original are great.

I currently approach my relationships as polyamorous, meaning that I prioritize being able to have multiple lovers and discussing the relationships honestly with everyone concerned. A while back, I wrote a piece called My Top Questions About Dealing With Multiple Lovers, in which I mused about some confusing thoughts I’ve had in pursuit of polyamory. My first question was:

What are my responsibilities towards my partners’ other partners? A lot of poly people will tell you that if you get into a relationship with, say, a married polyamorous man, then you must also expect to interact with his spouse. In other words, don’t assume that your relationship means you only interact with one half of a couple. I’m totally fine with this, but on occasion I’ve felt like I was getting sucked into the couple’s problems, or like I was expected to have no individual relationship with my partner — that I always had to go through his primary partner.

Sometimes, polyamorous people put this much more succinctly: “You can’t date half a couple.” If you’re emotionally involved with one person, you’re involved with their other partners by default … even if you’re not having a sexual or romantic relationship with their other partners.

A couple years ago, I dealt with a striking situation along these lines. I was careless … but I think my partner was pretty careless, too. He and I were highly attracted to each other from the start. He had a girlfriend, but I thought they were polyamorous. So I brazenly flirted with him in front of her, and got his contact information. She seemed calm and collected as she watched it happen; I really didn’t think there was a problem.

Boy, was I wrong. I went out to dinner with that guy later in the week — I’ll call him Ken — and we scheduled an S&M date. Ken and I agreed that we wouldn’t have any genital contact, although we planned to hit each other with things and inflict some pain and make out a bit. (Lots of people who are into S&M sort of separate S&M feelings from sexual feelings, but it’s different for everyone.)

Ken and I had fun together. But there was one thing I didn’t know until after the date was over: it was the first time in their relationship that Ken had ever done a private encounter with a different partner! And he hadn’t been very thoughtful with his girlfriend about it, either.

I found out the next morning, when Ken mentioned offhandedly that he was a little worried about his girlfriend. “How come?” I asked.

“We’ve never done this before,” Ken said. “I mean, we talked about polyamory a little bit, but we hadn’t decided to do it until you came along. So last night, she knew I was meeting you, and she’s probably been anxious about it all night.”

I got a sick feeling. I realized that Ken and his girlfriend had fallen into the “monogamous-now, polyamorous-later” trap. One of the big problems with being “monogamous now” and thinking about “polyamory later” is that if a potential Other Partner comes along, it forces the issue. Then, if the couple decides to be polyamorous, and it feels difficult for anyone … then the Other Partner can receive a lot of the bad feelings because the Other Partner is seen as the “interloper.” And I was now the Other Partner.

“Oh my God,” I said to Ken. “You mean you weren’t polyamorous when I met you?”

“No,” he said. I remembered how I’d blatantly flirted with him in front of his girlfriend, and I felt careless and cruel.

“I wish you had told me,” I said. “I wish you’d mentioned that this was your first time meeting someone outside the relationship. I would have suggested that you call her late last night to reassure her, or something like that. Do you want to call her now?”

Ken shook his head. “It’s nice to know that you would have been cool with that,” he said. “But now it’s the morning, and I’ll just wait until we’re done with breakfast before I call her.”

I thought about saying, She should be your top priority. I thought about saying, Maybe you shouldn’t date other women if you’re not sure whether they’d be cool with you calling your primary partner … but I held my peace. I decided that it wasn’t my relationship or my place to criticize him.

I felt a little uneasy about Ken, but I liked him a lot … so he and I thought about having a longer-term relationship. I decided that if we were going to continue, I wanted to do things right. I invited his girlfriend out for a one-on-one lunch so that we could talk.

It was hard to schedule lunch, but I was determined. I went all the way across the city to see her. When we met, she was nice enough … but standoffish. I asked if I could give her a hug, and she said, “No.” Then she said, “I’m sorry,” and told me that it was all a bit new for her.

We talked for an hour. I tried to make it completely clear that I didn’t want to be a threat to their relationship. But I also didn’t want to get sucked in to talking through their problems with her, and there were a few difficult moments where she told me about relationship issues. So I also tried to say, as gently as I could, that I didn’t want to be in a role of “relationship therapist” for their partnership. Although I felt open to talking to her and understanding her concerns, I really didn’t want to be in a position where I advised her about her relationship with Ken. I thought that could create conflicts where there didn’t have to be any conflicts.

By the end of lunch, Ken’s girlfriend said that she felt better and less anxious. But I kept feeling like I was barging in on a situation that was even more complicated than it seemed on the surface. I kept feeling like she blamed me, a little bit. Even though she seemed willing to deal with it, I was uncomfortable.

Although he wasn’t even there, that lunchtime meeting was the major reason I didn’t pursue things much further with Ken.