I don’t think he was lying back then about his intention to marry you some day. When he said that, it was a different circumstance. A different time, a different mood. he didn’t feel pressured about it, it was so far away in the future and was/is in love with you and happy when he said that.
Seems pretty clear that now he feels pressured about it, so he went defensive and maybe also a little nervous and that made him go on this rant.
It is not clear from what you wrote and I think we could only make guesses in the dark whether or not he doesn’t want to marry you at all because he doesn’t feel it anymore or because he’s just overwhelmed by pressure when things came close.
Do You still want to marry him in the medium to long run? If yes, give him a little more space and consider not pushing for it anymore. The more you let go now, the more he can approach you now so the both of you can meet in the middle again. You need to find a balance again where the both of you want the same things and go at the same pace to be able to have harmony within your relationship.
May i ask you, before you asked about the Wedding Ring, was your impression that everything was being fine and have the both of you been just as happy as you used to be? Or was there a bit of a decline? a good cause for his reluctance to go through right now could be that for some reason he is not as happy right now as he used to be and maybe that makes him a little cautious about going through with it right now.