Well I only have one... But it can work if you really plan ahead- and are flexible. The best laid plans can change when kids are in the picture.

Since I was a runner before I was a triathlete, it was more about getting in the run training when he was small.
I had him in a jogging stroller at 6 weeks. He stayed in that until around 4. Then he moved on to the bike with training wheels. By 5 he was on two wheels and I had to sprint to keep up with him.
He's 10 now, and just recently took over my old road bike. Yeah- he is as tall as me now! But the good thing is we can ride together. He's not quite as fast as I am, but he keeps up pretty good.
In the past I did a lot of trainer rides. Spinervals became my friend. In fact he loves to make fun of Troy Jacobson. FIVE< FOUR< THREE<TWO ONE.... And spiiiinnnnnnn.....
Also having a gym with a good daycare is nice.
I think if you can work it out with the husband so that you can get out at least a couple of times a week and then balance that with trainer time, you'll do fine.
Oh- also getting the rides in early in the morning helps too. You are coming off the bike just as they wake up. I'm in such a good mood when I come off the bike and then see that smiling face waking up.
Of course in the winter that will involve having a good light. But it's well worth the cost IMO.
Good luck! And congrats on # 2!!