My husband wants to have another baby but I don't

Me and my husband have 3 kids together and I'm 43 years old. I very clearly don't want more children. Why my husband wants more children is because him and our only son got into a fight. My husband is a Fisher man and has taken our son out fishing since he was 5. My husband took over his dad's business who took over his grandpas business and wanted to pass it down to our son. Our son has been his stern man since he was 14 and my husband made him make a promise to take over and he promised.... When he was 13. The fight is because our son graduated high school and has decided to go to college and he's going into marine biology instead. They had an awful fault and my husband accused him of breaking his word and the family business and our son said he made that promise when he was 13 years old. It was a really bad fight and our son left to stay with a friend. My husband recently told me we should have another baby. Especially since I haven't hit menopause yet. I told him no I don't want another baby but he claims he needs a son to take over or everything his family worked for is gonna die with him. I said we don't even know if the baby would be a girl and he said he still needs to try. I said I'm not having anymore kids and he's now giving me the silent treatment. I don't want anymore kids. My daughters are 14 and 16 and my son is 18. I don't want more children.