Please help me and advice me how to repair my relationship.

He's 44. I'm 40. He has two kids, 8 years old daughter and 6 years old son from previous marriage. I have good relationship with the kids and they love me. He's been separated for around 3 or 4 years and getting divorced in a month finally!
We have started dating a year and a half ago. and since then we've been seeing each other everyday. We traveled around 7 times together.
Shortly after we started dating, he moved in with his mom. Basically, I've never seen his place. He's mom has a small townhouse in a not very good neighborhood!
Since January, he moved with me. Before that he was staying at my place most of the time when he didn't have kids and then when he had even kids. Then I start getting frustrated to see the bills and I told him he got to pay. So he moved in and he pays!
Now, he has to move out again because of the kids' school being far from my house and his ex is complaining. He's moving back to his mother! Yes, at the age of 44, he wants to live with his mother!
These days, we argue a lot. He keeps threatening me that he will leave me. or he doesn't get married with me or no kids with me. But when he's good with me, he wants all these. He wants to get married, he wants to have child.
I have good relationship with his kids. His son is very spoiled and cries out of every single things.
He keeps teaching me what his son likes and what his daughter needs and what I have to do for him. I'm getting really tired of all the demands that he has.
I'm getting to the point that he doesn't add any value to my life, and he's taking my time away from me.
I really want to have a child and be married and have a life.
He makes good money, (he's a lawyer) but he spent the money on clothing and dinning out. Then he drives the dirtiest oldest car that I don't like to get into it.
I tell him to cut down some of your dinning out, and you can easily buy a new car. He doesn't care.
Basically, he doesn't have a house, or a good car. He has two kids which brings so much complexity to our relationship.
In one hand, I see him such a good person, caring, loving; but then when things don't go the way that he wants, he gets to be the meanest person exists.
I don't know what to do?
I'm thinking I'm getting really old to have a child and I feel he's my last chance, but at the same time he's taking my time (already a year and a half)!
It's not easy for me to break up with him. I'm so alone here.
What can I do? How can I communicate with him? He complains that I don't listen to him. The reason I don't is that whatever comes out of his mouth is criticizing and mean and I want to stop him. I beg him to give me a break and not talk for a little bit.
I feel he's hammering my head everyday.
I need some hope in my heart and understand how to deal with him. I know he's a good person. I want him in my life, but I got to figure out what to do.

Thanks for any positive feedback
M.