Have child from previous marriage S.o. does not

I have a child from a previous marriage my significant other has been with us since my child was on pre school. He has no children and has never been married. I know he and his family want both a wife and a child of his own. He won't admit it. But I don't want anymore children and never want to be legally married again but feel like I've taken his dream life from him. He is great to both my child and myself. Just don't want him to regret it later in life. I'm ok with it if he wants to leave and find that life I get and understand it. Just don't want to be eighty and then find out he was miserable