Husband said no to another baby...

I've been really depressed because my son used to be such a mamas boy. He went with me everywhere and we had such a close bond. Me and my husband agreed on just one child because I wanted all my attention to go to my boy. He loved me. Now he could care less. He doesn't want me to kiss him anymore or spend time with me. He would rather go out with friends and he just got a girlfriend. I can't stand his girlfriend because she's too clingy. He now wants to spend most of his time with his girlfriend and school and friends. I honestly just want my boy back. I figured I could have another baby and replace the love with this baby. When I talked to my husband he said my reason for wanting another baby is not a good one and what would happen when that one got older. I would honestly do everything in my power to make sure they still need me. Husband said he's not having another baby. How can I convince him. I think another baby would be good for both of us.