Living apart while in a relationship?

My partner lives with his adult son and I live on my own. I was hoping for us to live together by now (after being together 3 years) but it looks like it’s never going to happen because both places are too small for all of us and my partner doesn’t want to move. I also think his son will be living with him for a long time given the economy. I feel like if I have to pay my bills all by myself I might as well be single. What are your thoughts on this?