Husband wants to get a vasectomy but i still want more kids...

Anais

My husband and I are in our 20s and we have 2 kids. We have a 2 year old boy and a 3 week old baby girl. I’ve always wanted to have 3 kids because when i was younger it was me and my two brothers and life was good. I want one more baby but not till our 3 week old is at least 5 years old. My husband says we are good with the 2 we have right now. How can i change his mind about getting a vasectomy?? He’s hard headed lol i already told him i will get an iud for 5 years