Oh OP,
It's very hard to imagine a man so dim and obtuse not to to think your conversations 18 months ago would make you think what you did.
I actually find it hard to believe anyone could be that stupid.
He has indeed ruined any proposal with his behaviour and he needs to own that.
I'm glad you have stopped crying.
At the very least this must surely have taken a lot of the shine from him, which is no harm.
I don't know if he is good enough for you and you are still no wiser.
Personally I find it beyond manipulative that 18 months ago he bought the ring, but still doesn't know mind.
Maybe I'm just a jaded women, but I just don't buy it.
It's just a little bit too convenient.
I think he knew bloody well what he was doing.
Whatever you decide, I hope you think long and hard and listen to your gut, because I just think you are being played a little bit by him, despite his bewildered upset.
Is he really THAT thick?
To go to all the trouble of buying a ring when he's not sure of you at all.
Is he a bit manipulative in other ways?
Start looking at other behaviours to see if there is a pattern.
I would suggest you look at moving out to take some time to see how you feel.
It must be hard to look at him and this space could be helpful.