I'm in the same boat there but I'm training more consistently than I ever have. I have a double stroller so I take the boys running, or I load them up and do sprints uphill if I don't feel like going for a long run. It's not unlike pushing a sled. I also set the littlest one up in his bouncer while the 2 year old plays with the tools in my garage and watches me lift weights or do pull-ups. Exercise can and should be a family activity. On the weekends my wife and I each throw a kid on our back and go for a ruck in the forest.

You can also use children like a kettlebell. They love it and it's a great workout. The two year old also loves to help me with push-ups and planks by climbing on or under me.