I live with my Dom and their other sub and I'm jealous constantly. What do people do with that?
Impact PlayJealousy in a poly BDSM household is common and does not mean polyamory or the dynamic is wrong for you. Living in close proximity to a metamour, particularly one who shares your Dom, intensifies comparison and competition in ways that less proximate configurations do not. The feeling is worth examining rather than either suppressing or acting on immediately.
Jealousy in multi-partner households differs from jealousy between partners who live separately because the proximity removes the natural buffers that distance provides. You observe your Dom's interactions with the other sub in real time, at the texture level, which is very different from knowing abstractly that they have another relationship.
The poly community has developed frameworks for working with jealousy that are useful here, with some BDSM-specific additions. The distinction between jealousy and envy is practical: jealousy is the fear of losing something you have, envy is the desire for something someone else has. Knowing which is operating tells you what need is underneath it. Fear of losing your Dom's attention or regard is a different need from wanting what your metamour receives from them.
Talking to your Dom about jealousy, when you are not in its grip but when you are calm enough to be clear, is more useful than managing it alone. A Dom who is managing a household dynamic has an interest in knowing when one of their partners is experiencing significant distress. Keeping it hidden to avoid seeming difficult or weak tends to build pressure rather than reduce it.
The relationship with your metamour is often the underexamined piece. Some people in poly households find that developing a genuine peer relationship with the other sub, not as competition but as someone in a structurally similar position, reduces the jealousy considerably. That relationship takes time and cannot be forced, but it is worth investing in if the person is someone you could genuinely like.
If the jealousy is persistent and severe, it is worth asking whether the specific configuration, living together, is the right one even if the dynamic overall is right for you.