If you need a cleaner place to live, and their not assisting in this is causing you too much stress...
Do you have either a deal breaker, or a reason to live separately?
Just think about what you actually need.
I live by myself. At the moment, if there's a mess, it's my mess. If there is cat hair I can sweep it up. I do keep the bedroom door closed to keep the cats off the bed and off that carpet, because although I am not allergic, my Love is.
I WAS married for almost ten years, and the way we handled housework was that we both worked on housework, but different things(he was happier vacuuming, I was happier mopping) at the same time for whatever amount of time. We cleaned up our own dishes the day they were used. We each did our own laundry.
Housework agreements that are not followed can really cause a lot of hurt and resentment. If there are no consequences for your housemates and they can count on you doing it all....then you need to find some way of heading off the resentment that I know that I would feel in your shoes. They either need to find a way to compensate you, or, you may need to find a space for yourself free of pet hair.
The other problem is that of communication. You have talked about it, but, they haven't really understood or they have gotten away without any of the possible consequences. Boundaries aren't any good if you can't bring yourself to enforce them.
Good luck with your triad. I wouldn't be able to do a closed triad, but, I'm not you.