TL;DR my boyfriend aggreed to a poly relationship with our two friend but he can't understand that me spending time with another man (because women are okay) doesn't mean he's losing me, and one of member of our quad feels like they're just a stand-in for me when I'm not there and we're all lost.

I (29F) and my 8 year long boyfriend (36M) started a poly relationship with our two best friends (E and J) for a bit over two weeks. BF met J online 6-7 years ago and we've all been friends since, and E and J started dating about 3 years ago. The four of us becoming a polycule is something that had been very loosely/jokingly discussed beforehand, because we spend every other day together and it felt like the natural extension of whatever relationship we had.

Originally, BF was on board with this, but there's... problems, now.

I've spoken to BF before about how I'm poly, and that I would always, ALWAYS respect his boundaries and choices no matter what. We'd discussed opening the relationship a few years ago and when he said he didn't feel comfortable with it, I considered it an issue to be shelved until it came up again, if ever at all.

The way he says it, BF deliberately forgot about the whole issue in hopes to make himself feel better about our relationship. Because as far as he's concerned, if he doesn't have 100% of my time, love, affection and generally existence, he doesn't have anything from me at all. It's been hard not to compute that as, "Nothing you'll ever do is ever going to be good enough because if it's isn't ALL of it, it's meaningless."

Important to note that he does have previous childhood trauma that was addressed in therapy when he was younger, and that he is waiting for a callback from a therapist from an institution I recommended. BF was also homeless for some years, which he explains is the source for the "all or nothing" mentality.

E, J and myself and heartbroken and we don't know what to do. J and I have been trying to be the emotional pillars but we're getting worn out, desperate and hopeless. E, who's been in love with BF for a while now, also constantly feel like they're never good enough for BF, whose reassurances fall onto deaf ears. J and I do love each other, but it's hard to even say it now because of how it affects BF, and we end up "sneaking around" to not trigger him. (I say "sneaking around" because we mostly text, and only call each other where/when it won't bother BF.) Bringing up each other's names in front of BF makes him flinch, though less so now.

It's a whole mess. I know. And I know that this probably never should have happened at all. But we're here now, and none of us have any idea what to do. BF and I both considered breaking up the poly relationship, but what's causing issues for BF (knowing that I can be and am in love with someone who isn't him) won't be resolved with that. Breaking up with each other is also completely out of the question.

I don't know how to help BF understand that less than 100% of my time doesn't mean he doesn't get anything at all, and that me spending time with another man (because women, for some reason he can't figure out yet, aren't a problem at all; E and I can be romantic or explicit as much as we want and that doesn't seem to matter) doesn't mean that he's losing me.

DMs should be open, I'm open to literally any questions that can be asked. I'm running out of ideas and options. I've even tried talking to my parents about this, and though their understanding and welcoming nature was reassuring, they're just as lost as we all are.

Thank you in advance for reading this tangled mess of yarn.