So my girlfriend apparently also posted about this situation recently(we didn't coordinate this) so I just want to put a link so people can get both perspectives. https://www.reddit.com/r/nonmonogamy/s/cmCVdcoaM9

My (31M) and my girlfriend (28F) are in an open relationship, we are both able to see whoever we want gender wise and have decided to try things with very few restrictions and based on trust. We are new to non-mono and to our relationship so new situations arise pretty often that we talk openly about. We have both seen and played with people solo and have done some swinging. When she saw a guy solo for the first time last week, I really struggled because she had some of the best sex of her life and it took a lot for me to accept it and actively choose to continue down this path.

In the last day or so, my girlfriend has come to me and said she was going to meet a new guy next week for a drink then go back to his place. This would be the second guy she's meeting solo. I was taken back a little with the timing of it because we'd had a tough week after the first guy. But all in all I have accepted that my girlfriend will have sex with other people and enjoy it so I can deal with it. The goal is eventually to be completely fine with it. We had a later conversation where she mentioned that he was also non-mono but had a one penis policy with his girlfriend. This instantly rubbed me up the wrong way. What I can't work out is that if I'm making a deal out of it because I still need to do some work and just trying to sabotage her experience. Or whether my thoughts about the one penis policy are genuine and valid. In reality, it's probably somewhere in the middle, I need to do definitely need to do some more work for sure but I genuinely feel comfortable with her talking to and seeing other guys. I just don't see it as ethical and we just hadn't covered that topic before so the timing really isn't great. I don't think that view will change anytime soon and it's something I feel quite strongly about but I don't want it to be a huge deal. We have decided to have our relationship in an ethical manner, where we inform all our partners about our relationship status etc and I wouldn't force a OPP on her, I feel that is an extension of those ethics. I only invite people into our lives who are aligned to those ethics.

She argued that they have agreed to it and it's none of my business. I don't want subjects like this to come between us because in the future she's less likely to be honest about these kinds of things. But at the same time, I want to honour how I feel about the situation. I told her how I feel about it but didn't tell her what to do or anything like that.

She's pretty upset about me having this opinion and believes I'm just doing it to stop her from seeing guys because I can't handle it emotionally. She's wondering if I'm going to do this with every guy. I already know that I'm not. I was just about okay with it until I found out the OPP, then it just sparked a bit of jealousy in me but also doesn't align with my thoughts. If she did go and see him, I wouldn't see it as a betrayal or anything like that but it's just not how I want to live my life.

She makes the valid point that should she have to ask guys if they have that policy before meeting up? I don't really have an answer to that. I'm genuinely open to a solution and ideas here because I want to make sure my girlfriend and I are both happy and fulfilled in the long run.