Congratulations! My last one was 12 years ago, but I still think maybe I can help. Ids is right about one, thing – babies sleep a LOT. It’s just a matter of you and your wife/partner accepting that your lives will be controlled and ordered by the new infant’s schedule and sleep patterns for at least the first couple years.
The most important thing that you both need to remember is that you’re in it together. Work together. Each of you will need downtime or alone time every day. Make sure she gets hers, and when you get yours, use 15 minutes of it to play.
Don’t worry so much about “practice,” unless you want to in a given day’s window. Your goal is not necessarily continued improvement, but “regression avoidance” until you can devote more time. In the worst cases, that will be once school starts for the child, but that’s unlikely.
Use your guitar time to relax, vent, enjoy.
But never lose sight of the fact that SHE needs that time too, and if she’s nursing, she will need it more than you.
Congratulations, and good luck tomorrow!