Naming baby?

Emily
So we have all boys and my husband dominated naming them. Now baby three and I really want to name him. But my husband already decided baby boys name, Michael. I like it but...
1. Michael is his dad's name and my dad, David, feels a little left out even though his name is the middle name. 
2. I like Alexander nickname "Alex" 
What would you do? Go with what you first discussed or stick to my guns of wanting to change?  Michael David or Alexander David?
 Just to add we have James Michael and Nicholas Alan already.