Please be kind, this is new to me and I love him so much, I'm just really lost. Everything else in our relationship is perfect.

Tl;dr: boyfriend wants package deal non monogamy but can't deal with the thought of me having sex with other men. Can we still make it feel balanced in other ways (kink rather than penetration), or will resentment build up?

Long version

My partner and I have been together nearly 2 years and have been open to casual non monogamy since the start. We decided playing with others together doing threesomes, possibly swinging, kink, is the right fit for us. Neither of us want other relationships and it's purely about the sex for him.

As it is more his preference than mine it has taken a lot of emotional work to get to the point I'm ok with the idea of seeing him have sex with other women and he has been 100% understanding and patient with me. All good so far.

The issue is, I'm fairly sure I can't be in a relationship long term with a partner who can have sex with other women, but I can't have sex with other men. I'll end up resentful and insecure. Due to past relationship trauma, he finds the idea of seeing me with another man terrifyingly stressful and although he has agreed to work on this I hate seeing him hurting trying to figure it out.

I know I'm valid in wanting some kind of equality in this, but I also feel kind of sucky because I am 80% monogamous leaning, so I dont have a great drive to actually sleep with other men and the only way I actually enjoy it is in a kinky setting, rather than vanilla sex. The strongest of my feeling are out of stubbornness- if he wants to sleep with other women, he should be working on letting me sleep with other men. I dont want to feel like that though and I hate the idea of him doing this for some subconscious childish tit for tat reaction.

Would really appreciate outside opinions as I'm lost. I think my options are -

1. Break up (do NOT want to do)
2. Suck it up and find a way to be happy with us only including women
3. Stand my ground and let him work on his own trauma without me trying to fix things for him
4. Play separately (neither of us really want this)
5. Doing play with sex for him with women and doing kink/bdsm/limited sexual play with men for me.

I'm leaning towards 5 and I'm generally a lot more into kink than sex, but I would still have to deal with penetrative sex not being on the table for me.

Help!