Just to give a bit of background dh likes 'grown-up' 'professional' names. He's quite old fashioned in his views (especially concerning names) so naming our dc's hasn't exactly been easy!
Dd's name is millie, but her birth certificate says Amelia, so when she becomes a lawyer or accountant like her dad she has a 'name to give clients' as dh puts it

So with dc 2 on the way I have fallen in love with Coby obviously dh is dead set against this unless we have a 'proper name' to go with it. I was thinking Jacob, but are they 2 different unrelated names? Or would you say Coby could be Jacob's nickname?