The bottom line is that as much as people on here will tell you a number of things the simple truth is that:
You wanted to get married before you were 40, you wanted HIM to propose (you don't want to propose to him and I don't blame you), he hasn't proposed because ultimately it's not really worth his time or effort, or the expenditure.
There is a saying, why buy the cow when you can get the milk for free. That saying applies to your situation.
Why would he propose to you when you have stuck around for 13 years, not made a big deal about it, not really said anything and just waited like a patient little woman.
Now, the problem is that you're invested in this relationship now, and by and large things between you are actually probably pretty great so you don't want to feel like it's worth the risk of ruining the situation if you actually lay down some consequences, but at the same time you still want to get married, and you want him to care about that.
Well, he doesn't. He doesn't see the need, it's all very logical to him that he has everything he wants and spending a few thousand on a wedding/engagement ring/wedding ring/honeymoon is really probably not worth the hassle.
I mean you're there aren't you?
You go on holiday together already right?
You sleep together?
You likely own a home together?
So what exactly is the motivation for him when thus far you have done nothing and said nothing except every now and then, and it's really easy for him to just basically brush that off and you'll shut up again.
Do you see where i'm going with this?
It's up to you what you do, but you've got yourself in a bit of a pickle here so it becomes a question of, is this a hill you want to die on?
If it is a hill you want to die on then frankly, you sit him down, you tell him that you've always wanted to get married, that you feel like you've been ignored and dismissed, that it isn't acceptable to you, and that actually if he doesn't want to marry you then you don't see the point in carrying on with him because YOU want to get married.
It could be seen as cutting your nose off to spite your face, because like i said, you've left it 13 years here. You've tolerated it. You've allowed it. You're married in all but name.
If you left him you'd have to go back out onto the dating market again, find someone else, hope they are as good, hope they want to marry you and in the meantime sell your house and deal with heartbreak. He'd probably think you've lost your fucking marbles in the process.
But unless you make it crystal clear with this guy that actually you're not cool with this and you are SERIOUS about it, then nothing will change because you will get back in your box and shut up about it and slowly simmer over it.
What's more important? The relationship? Or what you personally would like for yourself in your life?