Howwww

So we have an almost 1 year old (on the 29th) I want my kids to be close together (1-2 years apart MAX), BUT my husband is saying no go for a kid until our baby is at least 2. It took us almost a year and a half to have our first so I’m looking at 3+ year age difference (and I will be 30 before our second… we want 3!!!) I know your fertility goes down the more you age. How do I explain this to my husband that if we want 3 we can’t wait too long??