Sad. No more children

I've come to realize that I won't be having anymore children. I have a 1.5 year old and SO (not married) does NOT want anymore. It's been really depressing and finally sinking in. We got pregnant after bc failed and never really talked about how many kids we each wanted before that. Also, are relationship wasn't very serious at the time we got pregnant, we were more FWB but now we bought a home together and decided we need to make things work for our child. He won't change his mind either, he's already selling the baby stuff he bought. What can I do In This situation? I'm happy with him but not with him not wanting more children.