OMG Op, I've been worrying about you. And I noticed there was an update so I read through the posts.
I disagree with above that you did nothing wrong. Sweetie, you were on the verge of being engaged and talked yourself out of a proposal there!
Your conversation:
Me- do you want to get married one day ?
Oh- yes. One day.
Silence
Oh - so when do you think would be a good time to get married ?
__
Why, why, why did you not say "well, before Easter". (Or before February / September or before mid summer??)
Please restart / continue the conversation ASAP and set a date.
It doesn't have to be the man down on one knee holding a ring! Having been proposed to on one knee it is embarrassing.
Just a conversation about the future / what to budget for in 2018....
So...
You need to say "Darling I want to make some plans for 2018 and our finances. Do you remember when we were discussing when I would like to get married a few days ago? (if you want to be more direct you could say 'when we would like to get married..._)
Him: yes.
You: Well, I know that you'd like to delay until we've had our second child, but I'd love to have a second child with you but I'd also like to get married before Easter. Is that OK?
Him: yeah OK.
You: Great.
(For god's sake don't tell him that you wanted him to do something more romantic, just enjoy the moment).
Then, you are engaged. If anyone asks, neither of you proposed, it happened to be discussed and mutually agreed. You should inform both sets of parents and if I were you set a firm date. If you don't have tons of savings, go registry office - a friend of mine did and it was actually really nice and romantic.
(This is no risk, because if he says NO, then you need to say "Oh, why not? Are you worried that we can't afford it?)
PS. If it all goes wrong & he says no, I don't want to be married, you can say 'oh, that's a shame, I love you and it is important to me.' If he cannot agree to get married, you could just accept that and if your family / friends ask you will need to say 'Oh xx doesn't want to be married. We will not get married.'
This happened with good friends of ours - he proposed to her (after she had given birth to their second child) and she said 'no'. She said 'if I had wanted to get married we would have done that years ago'. (He told all this to my dh). He was quite taken aback, but they are still together. Not married. 2 kids in primary school.
Once you have children you tied together for life.
Or, if you have some variant of the above conversation and he doesn't want to marry you (in the next few months), you could say well I (and child) are leaving. I am disappointed in your lack of commitment.
Sending you a hug from Australia.