I want one more baby but my husband is done

Hi there I'm looking for some different perspectives on this topic...

I always thought I wanted two kids. ideally one boy and one girl. I'm 24 and my husband is 25 we struggled with getting pregnant for 3 years with our daughter who is now 18months old. We had losses and a lot of months with no luck but were blessed with her. This past winter we had a surprise and I became pregnant, I'm not 25 weeks with a little boy.

My husband is saying he is done. no more kids he is good with two and isnt going to budge, he even said he will get a vasectomy since he isnt wanting more.

I feel like I'm too young to be done having babies, I didnt really want my kids this close and wanted to space them out to enjoy pregnancy...this pregnancy has flown by and I've been so busy with work, school, and my 18 month old that I hardly have been able to soak up any special pregnancy moments. I haven't even took my photos to announce publicly, the only people who know are people I see daily and noticed. I really want another baby in a few years when I turn 30 before I feel too old and so my kids can actually realize they are having a sibling.

Any advice on what to do? Am I being too selfish?