If marriage is that important to you then can I ask why YOU would put the deposit money down on house that he'll be sharing with you? Why would you do that before he was ready to make things legal according to state and church?
Maybe you should think about setting a date that you want to go to City Hall and make it official before you decide to allow him to move into your house with you???
Like: "I'd like to be married and expecting my first baby by 30, I'll start making preliminary arrangements after we move into the house." Then don't say anything else and see how he responds to that. If nothing else, it will open up a dialogue.
Why would he change a thing when he doesn't have to? If he has to, but he won't. Well then it's best to find out that you're with the wrong man now rather then later.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion