2girls but I want to try for a boy

So I just had my second child about 2 weeks ago. My husband says no more children because he's afraid that it will be another girl. (I have 2 brothers and he has 2 brothers) I really really want to try for a boy but I know it's a gamble. How would I go about convincing him to try for a boy? (And I mean in the future, about 2-3 years out) 
 I know deep down he really wants one, he was so sad when we found out we were having another girl. 😞