What would you do in my situation?

Looking for some honest advice. So my boyfriend and I of two years, sold our first house, and decided to move into a cabin that is on his parents property. Moving into the cabin on his parents property was supposed to be short term, until we found a bigger and better house for us to move in to. That had been the plan for a long time and we agreed to live in the cabin for up to a year while we looked for a new house to come on the market. Well a few weeks ago, my boyfriend told me that his parents are splitting up and so his dad doesnt lose the house, the land, and the cabin, my boyfriend is going to put his name on the mortgage with his dad. My bf then told me that it was already decided, and that this is what he was going to do no matter what, and that he is going to stay in the cabin (which is only 500sq ft, has no shower or tub, or laundry area, and 1 bedroom), permanently. That he no longer has any interest in buying another house and he is using the money from the sale of our old house to invest into the property and land. Well I said I don't think that was the smartest idea, and That I don't want to live in a shack for the rest of my life. He then told me that this was his plan and "no one was going to stand in his way." Not even his long term, live in girlfriend. So any thoughts on this? What would you guys do in my situation? I am desperate for any advice. I love him to pieces but lately he is showing me that he really doesn't care what my thoughts are on big picture decisions.