OP you sound like you are in kind of a fog of expectations and it is stopping you seeing the wood for the trees here.
Tell him you want to marry in 3 months and TTC straight afterwards. He''ll either agree, fuck off or try and placate you and string you along a bit more (and you'll need to leave and not look back)
Yes, you WILL always have the feeling that he didn't propose naturally to you and you had to push him forward and that isn't the way you wanted it to happen, and you'll never get to have it happen in the spontaneous way you wanted.....
That's how life is. Expectations fuck everything up.
Not having the spontaneous proposal and spontaneously deciding to conceive is the first of very many expectations about having children that you are going to have to deal with.
Many women (me included) have a set idea of how they want childbirth to go.....often it goes another way entirely that they didn't want at all and they have to cope with the fact that their expectations of birth haven't been met and will never be met......
Many women (me included) have an expectation of how life at home with a new baby will be....so for example I expected DH to be at home with me for a couple of weeks nesting away, walks in the park with the pram, registering the birth and have a nice celebratory lunch together as a family etc...in reality DH's mum had a stroke the day I had DS and DH had to spend most of the next week visiting intensive care. And i'll never have that peaceful family time with a new baby. But that's the way it is.
Women have these expectations about making friends with other mums at baby groups, about a second child and then can't conceive., about their careers after children that don't work out due to issues with childcare etc. I'm sure you get the point....don't let wanting it to be perfect take the chance to have a family away from you....
Speaking as someone who started TTC at 36, I wish someone would have given me a stiff talking to. I thought if you TTC in your late 30's, you had plenty of time.
The reality is, If you have no fertility problems, then you still have plenty of time. But 1 in 7 couples have fertility problems, and you don't know if you are one of them until you start TTC. And if you do, tests take time, treatment takes time, false starts take time, and you are getting older by the day and the success rates are declining every day that goes by and its a very tough position to be in.
Of my group of 5 friends, all of whom started late, 3 had no issues whatsoever, one couldn't get PG, had 5 rounds of IVF and is childless, and I had 5 pregnancy losses over 4 years before having DS in the absolute nick of time.
I was very, very, luck to have DS after making some stupid choices in my 30's based on some longheld but ultimately dangerous ideas of how I wanted life to be