My SO and I mutually agreed to not have sex or anything with our outside partners, but she told me that she has been physical w theirs once but she regrets it and feels like they were pressured into it. her partner didn’t say she had to but it was more like a guilt trip, as it sounds to me. I’m not necessarily mad at her but I’m just worried she’ll do it again or something else feeling obligated to because her partner tells her she thinks she loves her a lot. I trust my SO but I’m worried that she’ll be manipulated into doing something she doesn’t want. I don’t know how to talk to her about this without it becoming a “you don’t trust me” issue. I don’t want her to get hurt, by me or her other partner.
I’m confused about how you define “partners” if you are not having sex “or anything” (which I assume means sexual intimacy). For you and your SO, what is the difference between an “outside partner” and a “friend,” and are all these “outside partners” clear on this definition? Everyone has the right to define their relationships in ways that work for them, but it sounds like this arrangement is pretty standard monogamy - have emotional closeness with other people, but not romantic/sexual closeness.
If your SO is spending time with someone who manipulates and guilt trips her into sexual intimacy, that is NOT OKAY. Consent must be freely given, and it is not healthy to be around someone who pressures you into doing something physical that you don’t want to do. You can tell your partner that you’re concerned about her and want to make sure she’s safe in all her relationships. It’s not about not trusting her - it’s not saying “I think you are going to cheat on me again” - it’s saying “This person did something hurtful and not okay, and I want to talk to you about whether you want to keep hanging out with them, and if so, why.” You can let her know you support her and talk about strategies for asserting her boundaries and getting out of a situation that doesn’t feel safe.
If you make your concerns clear, and she decides to keep spending time with someone you feel doesn’t respect her consent or boundaries, you can’t control that choice. You can decide whether you want to continue seeing someone who involves that kind of person in her life, or whether the stress of knowing she’s seeing someone she may be intimate with despite promising you not to is more than you can handle.
[CW: the following section may be triggering to anyone who has been pressured into physical intimacy and was victim-blamed afterwards. I have a policy of taking people at their word when they say they were not consenting, but in this case, I want to give advice that covers another possible scenario.]
Of course, all the above advice assumes that everything you told me is correct on the part of everyone involved. It is possible that she did want to be intimate with that person in the moment, but knew it would upset you, and is choosing to not take accountability by blaming the other person. Setting boundaries that are so rigid - you can be “partners” with this person but not be “physical” - can sometimes lead to people choosing to violate those boundaries based on desires in the moment. Maybe the other person did initiate, but maybe your SO had more agency in the choice than she is owning up to. She may regret it because she knows it was a violation that would upset the terms of her relationship with you, rather than regretting it because she didn’t want to do it at all.
It might be wise to have a talk about why you two have set this boundary about sexual intimacy and whether relaxing it might prevent the feeling of tension and pressure that comes with wanting to be with someone when it’s forbidden, which can in turn make someone feel like they didn’t fully want to do something even when part of them did want to.