Not so much a case of ‘just knowing’ for us.
although, I never wanted kids, then when I changed my mind I only wanted one, then when that one was born I knew quite quickly that I wanted another. Part of me feels like it was because I had complications with my first, that resulted in an early planned c-section. So I mourned the healthy happy pregnancy I thought I’d have being a young fit women I didn’t expect there to be much to go wrong, naively - I also mourned the birth. I never experienced a contract, no braxton hicks, no show and although many people told me I was ‘lucky’ not to need to go through it, I still mourned it.
So we decided on another baby once I’d reached the ultimate ‘safe zone’ 12 months after my section. We agreed that we can afford a second child comfortably and afford to upsize our home to accommodate a second.. but we couldn’t finically afford anymore, and that if the next baby was complicated and resulted in another c-section then I would have my tubes removed, because then even if we could afford a third the risk to me and the baby with any subsequent pregnancy’s would be too high for us to want to risk.
We started trying 12 month after DD was born, conceived 7 months later and DS was born by emergency c-section. Which sealed our fate for us really. My body doesn’t agree with birth and we’re grateful to have the two children we do have. Unfortunately with the emergency c-section we were already scared and anxious to go in, so we opted out of having my tubes removed and decided DP will have a vasectomy instead.
I regret not having my tubes removed while I was already open on the table. If I could go back I would have said yes. So I guess that feeling of regret of not having my tubes removed confirmed that we just know we don’t want more kids, but there were a lot of previous factors that we discussed anyway that meant we decided not to have anymore.