I'm sorry OP, but I think either he doesn't want to have children and might never will, or doesn't want to have them with you :(
I'm not religious and am not too far away from you in age, but I note that you are his partner. I think it's very sensible to live with someone before you get married, but you've gone beyond that and now bought a house together.
I only being up the marriage issue not because it's necessarily important to you, but because there is a type of man who is quite relaxed about it all or says they don't believe in marriage. It's always next year, or when they're get a raise at work, or when things have 'settled down' somehow. There's always an excuse.
What they actually mean though, is that they don't want to marry you. You're not special enough. You're Ms Good Enough for now. Lovely, but not someone who really lights their fire.
The worst ones are quite happy for their girlfriends to have their children, and once that's ticked of, a lot of those women can forget being married.
In this case, it's not quite that bad, but he may have been mainly wanting to have a house, have a nice partner who loves him, and now he has both, may never feel any kind of urgency to have children.
Some people are always undecided anyway and some never have children. It's not necessarily anything manipulative.
However, be careful he doesn't string you along for years and years, only to leave you, find another (much younger woman), marry and have kids with her quickly.