Apologies in advance as this is long-

My spouse (32M) and I (27F) have been together for a long time. We've been poly for almost the majority of our relationship, even prior to marriage. It's always worked for us. It is part of what drew us to each other in the first place. We've always had great communication and boundaries. But this... This situation is new.

This is the first time where we've explored having relationships outside of one another. Like, not just hookups but relationships. And it wasn't intentional. I met my girlfriend by a complete... Happenstance. (It's actually kind of a beautiful story, but not pertinent to this post). I didn't anticipate meeting someone, but alas, it happened.

He was comfortable with me seeing her and trying to date. Then all of a sudden, after the first date, he wasn't. He keeps trying to be okay with it, then pulls the rug and says he's not, then tries to be okay with it and tries to even get to know her and everything is going GREAT, like, they get along so well ... Then all of a sudden, the next morning, he's VERY much not okay with it to the point where he wants to leave me OR he's demanding I leave her.

Then the next week, he's willing to try again. They have even sat down and had numerous conversations with each other, all of which end up being totally great, both leave the conversation feeling good and having communicated and then suddenly... He's still not okay with it.

He tells me he thought he would be but that he's not okay with "sharing me" (but yet, we've had many partners before, and he's been okay with "sharing me" before but this one... He's just not okay with)

She had a rough upbringing. She is a bit rough around the edges but she's an amazing human being. She's even the director of an entire homeless shelter. She's great. He just wants to pick apart any tiny "red flags" he may see when she talks about her childhood or whatever.

Mind you, we don't ALL hang out together all the time. But I live with him, and so when she comes to visit we sometimes hang out together (not all the time, but sometimes)

Now granted- I will be the first to admit that with this being the first side-relationship dynamic we've ever had, I have made mistakes. Classic NRE mistakes. For example, when I went to her house one night for a date, I got a bit too drunk and forgot to text him and ended up falling asleep. Big no no on my part. Or, not communicating with him fully about how much feelings I'm growing for her. Little things here and there that's I'm LEARNING from but were mistakes on my part nonetheless. Nothing like, life altering or damaging. Just... A learning curve. And he even admitted that- a learning curve. This is a dynamic that is unchartered territory for all of us.

Also, mind you, she has been AMAZING through ALL of this. Being respectful of our boundaries, being respectful of our marriage, communication and kindness, even going as far as to specifically communicate with him to help him feel more comfortable. She has been a damn godsent. Like, the patience on this woman is incredible, truly. She's gone above and beyond.

But still... He doesn't want me to continue. He keeps saying "I've told you how I felt since day one and all my feelings have just been disregarded". I've tried to cater to his feelings, adjusting how I communicate and how I approach things in order to be mindful of his feelings. Giving him EXTRA love and attention when it's just us. Being mindful with everything I do.

I understand NRE is a thing. And that definitely was a factor here and one that myself and my GF have tried to be mindful of, and something my spouse has learned what it even is. I understand that there are lots of mistakes that can be made in an NRE and sure, I've fallen into some of those but again, nothing life devastating. Nothing I haven't acknowledged, apologized for and course corrected.

We've discussed boundaries and rules, we've discussed what makes him comfortable and what doesn't. I have respected all those and STILL he doesn't want me to continue this.

It feels like whiplash. Everytime he says he's okay with it, and I allow myself to get closer to her or fall a little more for her, he pulls the rug out and says he's not okay with it. Even going as far as threatening to leave me.

This year has been rough for us. He was assaulted back in April and was in the hospital, he lost his best friend and lost his grandfather. I know there's definitely a fear of abandonedment coming out for sure. And I want to and am trying to be sensitive to that....

But I can't bring myself to break it off with her. I really like her. She has me writing again, something I haven't done in YEARS, something I'm really good at and love doing. We have a little book club going. Shes provided a source of comfort in talking about things that I can't necessarily talk to him about (her and I grew up with lots of trauma, and have gone through years of therapy, both of us, which is something he has been very blessed not to grow up with.. so her and I bond over how we have both healed from our trauma. I wouldn't say a trauma bond, but just like... Things I can talk to her about that she understands that maybe he wouldn't. And her and I sharing different tools that have helped one another through therapy, etc.) And that's just a few reasons why I really like her and have a really hard time breaking it off.

I just feel guilty. Because he's my husband, does that mean he gets ultimate veto? I mean, we both agreed to the poly life. We've been doing it successfully for SOOOOOOOO many years and it's NOT something we started doing to "fix" our relationship by any means (not like a ton of people get into poly doing). Does it even matter that I've really fallen for her? Or do I just need to break it off because my primary partner has "laid down the law" and is uncomfortable with it.

At this point, he just keeps saying "whatever, you do you. You already know how I feel about it" which just feels like... Ugh.

At this point I'm just ranting. I don't know what to do, and could really use advice from elder poly folx.