Future MIL moving into tiny home on the property against my wishes
My fiancé made the decision to put a tiny home on the property for his mother to live in despite me saying no and expressing how unhappy I am with the idea.
We've been together 7 years, engaged for two. His mother doesn't have a partner and never has been able to really be independent. She doesn't drive, doesn't know how to do basic things like sort her banking, get groceries or anything really. She relies on my fiancé to do it all for her.
When I first met him, his mother lived in the house with him. She had lived there for 10 years. When he asked me to move in, I said no. I'm not living with his mother. So we rented a small flat on our own for a year while she lived in his house. Then we moved her to a small flat round the corner and we moved into the house. She wasn't happy and started to get "sick". So she moved into a friend's house. Then she moved again, and again.
She has never made any effort to get to know me. Never asks me about myself or how I am. Every time she comes over she sits there on her phone watching videos on Facebook. I try to talk to her and I get one-worded responses. I feel like she doesn't even like me.
When me and SO got engaged I was over the moon with happiness and filled with lots of love. He soon after brought up the idea of a tiny home. I was apprehensive at first. Then the more I thought about the idea the more I hated it. The problem is, his house was purchased and put into a family trust long before I came along. So I had no say whatsoever.
A year ago we had a huge fight about him wanting to put her in the tiny home on the property. I didn't want it. But he went ahead and did it anyway. The house arrives at the end of this month and we are supposed to get married next March.
Every time I try to express how it makes me feel he dismisses my feelings, doesn't acknowledge that the decision should have been made together and keeps saying it'll be fine and he doesn't know why I'm worried. I cannot get through to him no matter what I say or how I word it.
On top of it all, she has two other adult children and none of them give a flying f about her. They never visit, never contribute, never even contact her. My fiancé is fronting everything and will be the primary caregiver when she can't physically look after herself anymore.
I am so angry. I feel betrayed. He made this massive decision without me, despite my protests. I am seriously considering selling all my stuff and leaving even though it will cost me tens of thousands in non-refundable wedding deposits and moving costs. Not to mention losing half my retirement funds and coming away with nothing because all his assets are protected by the family trust.
What do I do? Suffer for next how ever many decades living 2 meters away from needy dependant MIL and accept that I am not the priority in our relationship, or cut my losses, have my heart shattered to pieces and end things with the love of my life?