Your current life sounds idyllic. Why on earth would you want to change it by introducing a little bomb into the middle? (in reality that is what pregnancy, a new baby, and 6 years of broken nights / toddler tantrums / etc would be). It also might bring love, hope, gentle appreciation of everything that is family... but it would the the former that would create the havoc!
dh and I had a similar debate when youngest dc was 7. We each (separately) write down pros and cons, then compared lists. I was a little heartbroken because dh's conclusion (having done his pros and cons) was that we should stick where we were. My list was similar but the conclusion was to go for it. tbh I could not disagree with any of his pros and cons, nor could I disagree with his conclusion. I think my list had more emotional bias.
However, for me (from about 2 years after that difficult decision) I was totally happy that our decision had been to stay as we were. One dc developed mh issues (totally unexpected and needing lots and lots and lots of time and input), I left a stressful employment situation and set up my own business, we've had family adventures holidays in Asia and family sailing holidays in the Caribbean (both would have been almost impossible with another younger child), we've been able to support aging parents when they needed us.
The above, also sounds idyllic, but it wasn't. Dealing with teens and elderly parents simultaneously stretched every ounce of our time, patience, resolve. Of course we would have 'coped' if a baby was added into the mix, but for us, it was much better to have remained as were are.
I also think it's interesting that you discussed the possibility with your dc. It's good, in that you're taking their opinions into account, but it's also unrealistic. They have no earthly idea about the impact of this decision. It's like asking whether you should get a puppy, every doe-eyed person (adult or teenager or child) will say 'yes'. Then who ends up taking the pup / dog out at night in the cold and dark and rain?
You can tell from this, my answer would be 'no'. So what else can you do? What other exciting joint projects can you, your dh, your family get involved in?