We loved each other deeply
I'm sorry OP, but I think you should consider the possibility that he didn't, or not as much as you thought.
There should be a page on Munsmet somewhere of all the threads of women exactly like you, whose partners were also dragging their heels like this, didn't want long-term commitment (apparently), marriage was 'just a piece of paper; (apparently).
What often happens is that they break up and he goes for a woman that's a decade younger, marries her within a year, and she's pregnant sooner after. Really - look it up. It's a common occurrence.
I'm afraid this is how many men show that you're not 'The One' for them. They're quite happy to plod along for years in monogamous relationships, sometimes even buying a house with the woman, even having children.....but marriage? Nope. That's reserved for 'The One'.
but he never wanted that sort of lifestyle ......with you.
He was okay with us staying as GF/BF forever, and he was even ok at the thought of us being "husband/wife" and living together but in name only, not legally in court
I bet he was. That's because your situation was on his terms and he was already getting most of what he wanted.
Have you ever heard the saying 'Why buy the cow if you're already getting the milk for free?'. It happens a lot to devoted, lovely women who just isn't 'The One' for their male partners. They are Miss Right on paper, they are what most men should want in a wife, but they just don't tick enough of the right boxes for some reason.
I think it's a very good idea that you're not doing to start things or have sex with him again until marriage.
However, be prepared that if he does agree to marry, he's a bit a of a liability and more likely to be unfaithful in my opinion. In his heart, he'll still be looking for The One, and a change of heart now is very likely going to be him having a bit of a panic about his age or losing you for good to another man.