Part of me thinks he doesn't want the commitment and is scared of the financial aspects of marriage in terms of joint finances (even though we own a home together)
I'm sorry, but that's the palatable version that so many women tell themselves.
The unpalatable version that takes a lot longer to realise, often when it's too late, is that you're not The One.
He may say that he loves you, he may act lovingly, but it still doesn't mean you're The One. That woman that just hits them in the heart, and they know there's no way they want to risk any other man marrying that woman.
There was a thread just like this about a week or two ago which I also commented on.
There are so many devoted, loving women who end up with men that just don't love or value them in the way the women want. They often buy a house with the woman, and sometimes even have children with her.....but marriage? No. That's reserved for that special woman, if they ever meet her.
That's because in things like house buying or children, there's something in it for them. These days, they might not be able to afford to get on the ladder at all on their own, and many men have children because they want to father children (their genes) with a nice woman, not because they want to become a father.
They don't see marriage that way though, and marriage is only something they'd be motivated to do with The One. Obviously, there are horrible men who think they can lock down and start abusing & controlling women once they're married, so their motives aren't always good, but generally, I'd like you to consider what I've said.