I don't know what to tell you other than it is what it is and to hang in there.
Let some things GO -- totally or to other people to handle. Cleaning, cooking.... online shopping, online bill paying, crockpot/freezer meals are your friends. See if some other parent is willing to swap -- watching kids, doing chores.
If it is adult interaction in general you crave -- take the kids out to playgroups, library story time -- as much for your own mental health to alleviate cabin fever as anything else. Participate in things online where possible when babies are sleeping.
I count kids in the polymath
mix. The kids needing things will be felt across all tiers. They may not be lovers, but you are still in intense relationship with them and they still take up your time.
Talk to your poly people about time management needs, and need for couple time alone and how to balance it all out to the "good enough for now" place. Because the kids will grow and the needs will change.