That's so so so hard when one partner wants another child and one isn't certain or just flat out doesn't want another. When I got pregnant with my third child, I just KNEW. I know that's not helpful but it was literally just, "wow, my family is complete." I love seeing itty bitty baby clothing and tiny newborns but I don't feel that overwhelming urge to hold one or have my own. I have been SO easily able to get rid of our baby stuff and move on. I'm EXCITED to see her grow instead of being wistful at my baby no longer being small. Probably around 18months with my first two children, I started having that baby lust again and wanting another and that 18month mark came and went with #3 and no feeling. I just feel complete and done now. I look forward to my girls all being old enough for needing me less and being able to do things like traveling and being done with diapers and the like.
It must be hard to be so conflicted on this and I don't know if you have already sat down with your partner and told her how strongly you feel like you don't want to carry and birth another child but you sound like you need to. She may know your feelings but not know the strength behind the conviction that you truly do NOT want to carry another child and be pregnant again. If you does not want to be pregnant than maybe adoption is an option for you two. I know that may not give you exactly what you want but since neither of you want to be pregnant and you both seem to want a sibling for your daughter, that seems like a viable option.
Good luck with this. I think a serious heart to heart over a bottle or two of wine seems in order. This is why compromise is such a HUGE part of relationships. :hugs: Best of luck to you in whatever you both decide.