My fiancé and I recently moved into our new apartment, we have his sister staying with us since covid began. We picked our new apartment to fit our need, which included garage, laundry and two bathrooms. The plan was that the sister would pitch in and so we counted our chickens before they hatched. She currently has a part time job, she hasn't reached out to try for a full time, but recently purchased a new car. I leave the finance between her and my fiancé between each other.
Now I am seeing my role in the relationship as a key player become diminished. When visitors come over no one gives me any sort of heads up, I feel like one of our cats, finding out as the guest is arriving. My fiancé is opening up a bank account with her, he is uncombining our finances. It just seems I am becoming smaller and smaller. I want to bring it up to him again but he argues I am overreacting and he is not tossing me to the side. We don't have couple dates because the 3rd wheel has to come along. We do not even go work out as a couple anymore either because she goes with him, I'm no longer invited. He's off on days of the week, while I am off on weekends, and when our schedules match up we don't mix anymore, he has spent his good topics on her. I feel so stupid for feeling jealous of his sister, but i feel she has overstayed her welcome.
Its gotten to the point where I feel like the cook, cleaning lady, cat feeder, and rent payer without much say or role in my home, I didn't want to be stuck in the house alone on the weekends and took up a second job. I don't like heading home where I feel like a piece of furniture or a 3rd wheel on their relationship. If I bring it up he'll want to argue and since last year my mental health is not in a place where I can handle that. Please advise on how I should move forward, I am reaching my limit, I am also 6h away from any family and trusted friends, he is literally my rock here... and I don't think he understands.