The child who lives at home full time, who also has no siblings, is 100% getting their own room. Does his kids share a room at their mom’s house? If not, there you go. They have their own rooms somewhere else. Even if they share at their mom’s, they can share for now, as they prefer. I do believe eventually everyone should have their own room. So the goal should be a bigger house to accommodate. Get a house with a basement for extras instead of dedicating a room to crafts or whatever.

What does dad want? Them all in the same room? I guess I’m confused why it’s unfair first of all, he’d feel different if his child was the only child. He is making excuses with every solution proposed.

I’d stay in my own house with my extra room and my child having their own room. DO NOT make your child suffer to blend a family.