First time posting here, bear with me!

My primary (29m) and I (32f) have been practicing CNM for the past three years, been together just about five. We have strived to have a somewhat kitchen table dynamic so that we can at least be friendly with our metas. Our relationship has been beautiful, complex, and healing for the two of us in extremely positive ways. We travel together, spend lots of time with each others families, live together, lots of the privilege of being in a long term relationship as primaries. We were monogamous for the first couple years together but have always placed a strong emphasis on each other’s autonomy and independence outside the relationship. It hasn’t been easy, but always well worth the work to adjust to a more authentic style of relating and communicating with each other. I’ve been in a LT relationship with my other partner (31m) for almost three years. We sort of describe where we are at now (better than ever and feeling truly stable for the first time consistently) as a success story from “trial by fire” due to the insane overlap in each others lives and navigating the serious paradigm shifts from mono to poly. I’ve also had experiences with satellites and friends in this time period.

My primary on the other hand has not been with anyone but me for longer than several months at a time. He expressed he was never looking for another big relationship but wanted to have more open honest love and connections with others when we started this journey. (Disclaimer: I didn’t expect to fall so in love with my other partner and have two very enmeshed LT relationships, so it goes) His communication with his new partners has wavered from being solid to negligent. The first time he finally slept with someone outside of our relationship he didn’t let me know his intentions and told me two days later after we had had sex multiple times. I felt blindsided and devastated by the breach of trust. I let him know I didn’t care that he slept with someone else but I was so sad that he felt like he couldn’t communicate that this was something he was planning on doing. We have an agreement of communicating intentions ahead of time so that we allow space for each other to mentally prepare. He owned up to his mistake but also made a lot of excuses many of them based on his inexperience. We eventually moved through this but it was a huge fracture that seemed to stack with other little“mistakes” from before in my mind.

Fast forward a year later I’ve been dealing with a general bit of chaos and instability in my life (health, work, family, etc) all piled on. I decided to take a month and go on a solo trip abroad to get back in alignment with myself. My primary and I both set the intention of when I returned we would sink back in with each other and do some relationship tending. But surprise! While I’m gone he becomes invested in a new relationship, one with lots of overlap in our lives. She was only supposed to be in the area for the summer and I could tell this was a huge deal for him so I decided that I could sacrifice some of our time so he could develop this relationship with her (28f). Communication started strong on our end but I felt like he began to take advantage of the fact that I was open arms. (I.e. having her around all the time, not making plans with me, etc.) I didn’t realize how badly this was upsetting me until about a week ago when I got sexiled from my home at 12:30 at night when I was supposed to work early the next day and I had specifically said I would be home late and we had plans to share a bed, make breakfast together, etc. Not sleeping with partners while the other partner is home has been an agreement with both of us since the beginning. Luckily my other partner was okay with me staying over but it completely threw off my sleep and my primary’s excuse was he got “way too high and forgot to check and ask earlier” just really got carried away and thought if he texted me she was staying assumed I would stay with my other partner.

We decided to take some space and come at the conflict with a restorative conversation but before we could even plan one he dropped on me late at night a couple days later that he was planning on having unprotected sex in a couple days with his new partner before she moved away from town. I was jolted by one) the timing and two) I didn’t feel comfortable bringing someone else into our cule in terms of barrier free sex (which we have always had together) that was relying on an STI panel that was only 3 weeks after her own unprotected sexual encounter outside of my primary. It felt rushed and horrible timing as my primary and I haven’t had solid time to repair our relationship. I told him my issue wasn’t with him having unprotected sex ultimately it was the lack of risk assessment for one experience that bothered me. It would change our intimacy and that hurt. Basically, he got heated and decided that this was what he wanted to do regardless of our relationship because he may “never see her again”. I feel so hurt, confused and a bit neglected from the NRE he has been experiencing. He kept telling me it wasn’t a big deal and that even if we use protection for a few months we’ll be okay and it was worth it for HIM. Which I cannot simply see as not being selfish as fuck (I definitely see the side of I cannot control his actions but I had just hoped he would have greater consideration for our relationship which I have strived to consistently do during our poly journey) I’m doing my best but I’m finding myself feeling resentment for the limits he imposed on my budding relationship with my other partner. I’ve intended to not do the same because I didn’t want him to deal with that level of pressure but I feel like he’s been trampling over me and had quite literally stated “he’s just doing what he wants because he doesn’t want his relationships to influence what he wants”

I’m feeling like the breach of trust and little things has put me at a tipping point to where I want to break up. I’m so deeply in love with this person and we have built a beautiful relationship together but I’m afraid that he has patterns he can’t break in relationship with me. So far his non monogamy has not felt ethical. Am I overreacting and risking ending something that I’ve put so much care into over something we could move through?

EDIT some more deets: I’m barrier free with both partners, the person NP was seeing was more of a fling that has been about a month and then they are planning on moving away and traveling for a indeterminable amount of time as of the other day. NP is also not thrilled about waiting to have unprotected with me for 6 weeks while I wait for results while I’m having unprotected with my other partner. He kinda wants his cake and to eat it too. I feel like that’s tough shit. This is an added stressor. I know there are messes here but I didn’t lay the groundwork for all of this on my own in terms of the agreements. He had a large part in choosing what he wanted them to be and omitting them when he felt like it during this recent fling.

TLDR; primary in otherwise loving 5 year relationship has a history of poor communication in CNM, breaking agreements, overshadowed relationship repair for NRE and barrier-less sex with new partner, I’m overwhelmed and thinking of ending things