"There are lots of opportunties to talk about how you feel without saying outright i want to get married to you hurry up! Discussing a tv/film, discussing a thread on mumsnet you have seen , discussing a friend who has been waiting a long time for her bf to propose. etc"
Oh Christ, please don't do this.
Have the conversation or don't have it.
Don't start dropping heavy hints. He won't get them until they're really obvious and then he'll feel like he's being manipulated (which he would be).
"Or maybe he doesn't want to get married to you. Unlikely, as you live together, you have a child and he is raising a child he is not biologically related to. "
Actually I think this is bollocks. I have known a lot of men what will just go along with things for years without any real sense of commitment to them. That's why I'd never have children with a man unless we were married and I was sure, from talking to him and his behaviour towards me, that he loved me and wanted us to be a family.
It sound like the OP has fears that this guy doesn't want to marry her because he doesn't love her enough. If that's the case she really needs to know and make decisions about the rest of her life accordingly.
A tip: if he says marriage is "just a bit of paper", then he will almost certainly marry the next girl he goes out with after you guys eventually break up.