It's a real risk to wait for him because it might bring you problems. He might change his mind, but he might not, and if he doesn't, you will be left having to start all over again at the age of 30. Lots of people do meet other at that age, but unless a man wants to commit and marry quickly, they will try to go for someone younger, to buy themselves time. It's a lot of pressure because if they do want to split up from you because things just don't work out, it means potentially breaking up with a woman at quite a crucial time, and some men won't want that responsibility or pressure on their shoulders.
You probably don't want to think of your boyfriend in this way, no one does, but do consider that despite how nice he is in many other ways, you may not be 'The One' for him.
In my opinion, this is how a lot of men show their pickyness. They will even have kids with the woman......but they won't marry her. It's a way of keeping her at arm's length. They will shrug their shoulders and put a massive wet blanket over the whole idea, knowing it'll discourage the woman from expecting it. Or they will string the woman along for literally years, always promising that it's going to be next year, or when they get a promotion.
It doesn't matter how you feel about marriage - you may be quite ambivalent about the whole idea or might be politically against it even. But it's not about you, it's about what it means to the other person.
Please don't be one of those women who end up coming on Mumsnet, who at a crucial stage in their lives are dumped by their partners, only to find out that he'd found a younger model, married her and had kids in quick succession. No messing about. Suddenly he has no problem with marriage being 'a piece of paper'! Fancy that! The woman will often risk being left childless and alone.