First thing congratulations and get ready for the best of times and the worst of times..
Echo the comments above about using the commute to work to get a good ride in either a longer route in the morning or a longer ride home is how I did it but be prepared to be absolutely knackered from looking after a small child & sleepless nights & biking into work but it does work as I did it for a couple of years from birth…
However it does get better mine are now 4 years and 13 months and I get out 4 times a week now but all the riding is done after 7pm during the week or I’m out for about 7am on sat & sun, all my riding is now local to cut down on wasted time and I limit the rides to 3 hours on the MTB/Road bike which still gives a good home life balance…
Just remember it won’t last forever and enjoy your time with the young one as it goes so quick…
PS Turbo & Sufferfest & Trainer Road can also be your best friend