As others have said be very wary of spending money on his house, in any form, as you have no rights at all as far as it is concerned.
An old boyfriend, wanted me to buy a flat with him, as he couldn’t afford the mortgage by itself.
It was decorated in a man’s style as the current occupant was a single man, and that’s how he wanted to keep it, with the spare room the home gym. There was only one parking space and that would be his, it wasn’t clear where I was supposed to park.
I was OKish about buying a place together, but I had more in mind, a house, garden, shed, and a cat, with parking for two, which I ultimately did get, but not with him.
I bought it myself, and my now husband moved in with me