"Although it won’t be a new experience for him it will be a new experience for US. We make a good team and ideally I would want to experience this with him, even if I had experienced it before."
But OP....you don't actually know that if hypothetically you'd already had kid(s) that you would want to repeat that experience with someone else. That's just a fantasy.
Also you're falling dangerously close to the line of thinking that if he loved you enough, he would want to experience having a baby with you...and that's a flawed way of thinking.
If someone doesn't want children or more children, then they feel they have enough love existing in the world around them & no need to create more people in order to experience love.
A child isn't a symbol of the love between two parents. Children are their own little people & while you say we are being negative about parenthood, you seem to have a rosy vision of it - one that makes it crystal clear IMO that you are not a childfree woman, so it sounds like you are making the right decision for yourself to prepare to leave over this.
You don't know that your hypothetical kid wouldn't be born with a defect or special needs & you could suffer from PND/PNA and have a hard time of it and days where you just don't feel like being a parent.
This idea that this baby will be a new "thing" you experience together sound naive & simplistic. There would no doubt be at least one time where he turns around to you & says "well it was you who wanted this" while you're crying about the hard day you've had.
It wouldn't be the fairytale you imagine because parenthood is hard & raising children can test relationships to their limit.