name debate with SO

Marissa
if we have a boy, his name will be Edward Peter (the fourth). I don't disagree with naming him after the family but we're butting heads on the nickname. 
Ed is babies grandpa
Eddie is my fiancé 
Edward is too formal in my opinion. 
I want to call him Peter because it's different but my fiancé thinks "Eddy" but I don't want two Eddies in my house, that's gonna be confusing 😂
I want to pull the "I'm carrying the child I can name him" card especially since I'm letting him pass his name on but I don't know how he'll react to that lol. 
Opinions, ladies?