I think demanding it as a first name is a little unfair, especially given it’s a bit of an usual name. I don’t hate the name [name_m]Guido[/name_m], but I definitely had to search for it to find the meaning and make sure I knew how to pronounce it. It actually does have a lovely meaning (guide, leader), but it definitely was a slur at one point in the US.
Some Italian suggestions that sound a little nicer and could potentially be nicknamed to [name_m]Guido[/name_m]:
Giana
[name_u]Gianni[/name_u]
[name_m]Giovanni[/name_m]
[name_m]Giuliano[/name_m]
[name_m]Giulio[/name_m]
[name_m]Giuseppe[/name_m]
Giusto
Or, some names with the same or a similar meaning:
Enzo (ruler)
[name_m]Aldo[/name_m] (old and wise)
[name_m]Alessandro[/name_m] (defending men)
[name_m]Alfonso[/name_m] (noble)
[name_m]Dario[/name_m] (kingly)
[name_m]Edmundo[/name_m] (prosperous protector)
[name_m]Gregorio[/name_m] (watchful)
Or maybe you can convince your partner to use [name_m]Guido[/name_m] as a middle if the meanings flow well, like in a way that honors [name_m]Guido[/name_m] even more.
Leonardo [name_m]Guido[/name_m] ([name_u]Brave[/name_u] [name_m]Lion[/name_m] + Leader)
[name_m]Dante[/name_m] [name_m]Guido[/name_m] (Enduring + Leader)
[name_m]Davide[/name_m] [name_m]Guido[/name_m] ([name_f]Beloved[/name_f] + Leader
[name_u]Elia[/name_u] [name_m]Guido[/name_m] (God Has Answered + Leader)
[name_m]Matteo[/name_m] [name_m]Guido[/name_m] ([name_u]Gift[/name_u] of God + Leader)
[name_m]Nicolo[/name_m] [name_m]Guido[/name_m] ([name_u]Victory[/name_u] of the People + Leader)
I stuck with Italian names for you, but there are lots of names of course that could fit either way. Good luck!