Getting married and having a dream wedding seems to be very much a 'female thing', speaking from my male point of view and with experience of fellow chaps' outlooks on life - society seems to impose on girls this Cinderella idea of being swept off their feet by a swoon-worthy, tall, chiseled hunk and being his princess. Many men-folk (sadly) seem to be brought up instead with this idea that they should be sleeping around and adding notches to their bedposts to be 'a man', with no discussion about the whole creating a partnership thing, so the two upbringings seem to be diametrically opposed.
In reality a good marriage is about finding a best friend that you can talk to about absolutely anything, someone who will have your back through thick and thin, someone who will be by your side and holding your hand, but this never seems to be taught at any stage of education, and the 'celebrity' lifestyle of getting married then getting divorced two years later hardly creates a positive image or learning tool.
Personally speaking, I was not fussed by marriage, I never thought it would happen, but my other half basically laid it on the line after about eight years and said she didn't want to wait around forever. (She also counts the four years before we got together on top of that, although I call that stalking

lol.) I somewhat reluctantly came round to the idea - I like to keep my options open in life because I worry I will miss out on things if I choose one particular option, be it not committing to buying a specific new TV till I absolutely have to and have done a load of research, not getting tied into a 2-year mobile phone contract, not deciding on the material for a wedding suit until the last possible moment... so the idea of committing to one guaranteed path for the rest of my life was scary.
Having done it, I'm very glad I did. It is a nice feeling to know that you are both looking out for each other and are 'in it together' as a strong partnership
Perhaps, like me, your boyfriend doesn't want to rush things or feel pressured into doing things. Perhaps he wants to savour the steps towards the big day rather than rush through everything
now. Perhaps he is worried that getting married again risks a relationship breaking down again - it happened once, so perhaps his logic is that by not getting married or delaying it as long as possible, it can't happen again?
How old are you both? If he was married before his last relationship and that relationship was 9 years, was he married very young?
Do you feel the added pressure of your bodyclock ticking loudly? (My good lady has basically always wanted children and is constantly worried that she will not be able to because she is older now than she used to be.) If you have not talked about children, you need to do it now - because if you want them and he doesn't, it may be that he will never change his viewpoint and you will have wasted time seeing if he will come round. Me? I am coming round to the idea, which I never thought I would.
It does seem like you both need to sit down and have a serious discussion about what you both want out of the relationship, to make sure you are both on the same page - and if you're not, a decision needs to be made.
Both men and women can change their point of view with life experiences (such as I like being married whereas before it scared me, and kids are a possibility now) but if he
definitely doesn't want certain things you do, perhaps it's not meant to be.
Anyway, I am some random on an anonymous internet forum pontificating over details of your relationship I know nothing about, so my opinions should be accorded an appropriate amount of weight - communication is the key thing you both need to focus on, to understand what each other are thinking and why, as already mentioned by other posters. I am hopeful that if you both understand what each other are thinking and why, it will make your relationship stronger
