Maybe you should ask your son and see if he really wants to have a brother or sister. If so, you can sit down with your husband and try to explain to him why you want to have another baby. Ask him if he worries about anything. Maybe he has his own reasons which you don't know. It is best to communicate with your husband rather than trying to get pregnant without talking to him first. After all, it is a matter of the whole family so better get everyone's input before you draw a conclusion. Wish you luck.