I hope we can find a resolution as well.
I am ok with blunt. I am not ok with having my feelings deliberately invalidated, being told I have a chip on my shoulder, am being ridiculous/unreasonable by even posting the question, and that I act entitled. That isn’t directed at you specifically but rather at an overall theme in the responses I received. Kindness and bluntness are not mutually exclusive, and bluntness and rudeness are not synonymous.
I appreciate your kind reply, and I am hopeful that my partner and I can sleep in the guest room in the future with a new mattress if necessary, or that he’ll propose an alternative solution that works for everyone.
I apologize for the heated words of some of the posters here too. I don't think I was being judgmental, myself. I asked whether all 3 of you were sharing the one bed, and if so, why? Or maybe wife sleeps in the guest room when you spend the night, and leaves you and bf to sleep together with the (unreasonable, unrealistic) order to just sleep in the "master" bed, but not have sex on it.
As a queer (pansexual) woman, I don't call only intercourse "sex." There are other forms of sex. What if bf got hard in the night, touched your breasts and humped your ass, without penetration of your body? I mean, that kinda stuff happens with people with libidos. Did the wife forbid him to get an erection while sleeping or half awake? Would he have to roll over away from you and force himself to deflate? It's just so unrealistic. What if you got turned on being next to your lover? Would you be "allowed" to masturbate, to get a release, to be able to sleep? It seems no one has thought this through very well.
I guess you could always have sex in the guest room first, and then move to the comfortable "master" bed for sleep. Where does wife go? Does she sleep in the guest room where you and her h just had sex (who changes the sheets?), or does she sleep a trois in the master bed with you and her h, knowing y'all just had sex in the other room, and might still be wearing each other's essence?
It's never OK to just repress your feelings and try to brush things under the carpet, in any adult relationship. But it's even more important in polyamory, to learn how to express your feelings respectfully, and feel heard, and be able to let your partner express their feelings, and really hear them. Then, after that, you make your plans. And any guideline you do come up with is always up for renegotiation. There are no vows, no "forever and evers." A guideline that worked in 2020 may no longer work in 2022.
I understand the issue of him just wanting to sleep on his comfortable mattress. It's funny to me that his wife is OK with you sleeping in the bed (with or without her also being in it), but not having sex. We all sweat a liter of water through our pores every time we sleep in a bed for 6-8 hours, after all.
A more comfortable guest room mattress is the only long-term solution. Until the purchase is made, if I were you, I'd sleep in the guest room, with bf cuddling/fucking you in there, as desired, before and/or after sleep time. At least the wife is OK with you sleeping and having sex in her house. Some metamours don't like their partner's OSOs to have sex in their house at all. Some barely want them to come inside past the front door.
I'm glad you came here for advice.