Loosing my freaking mind

I know this is SUPER dumb. But honestly I need advice. My SO and I have 1 son together right now & are pregnant with baby #2... We only plan to have 2 kids.... In his family, his dad used his grandpas name as his first sons middle name, and his name as my SOs middle name. Which is cool. Whatever... 
Well we name our son and his middle name is his grandpas... 
Now we are sitting here discussing names, and as much as I don't want a girl, at this point I pray that I'm pregnant with one because we have a full name picked out & have since we were first pregnant with our son. (It's after his mom who is deceased, so I have ZERO problem using it!) anyways...
 We are NON stop fighting over the name. I want my dad to feel special so if we have a boy I would like for his middle name to be after my dad. But my SO IS FLIPPING OUT on me because it is suppose to be like his family. On top of that. Every single boy name I've suggested he is COMPLETELY against because his ex fiancé of 4 years wanted to use apparently all of them.. Like how is that fair to me.. And when the f does my family get to come into play... It's so frustrating. I don't know if I'm blowing this out of proportion or what. I could use some words of advice... Or encouragement bahaha.