Yeah, been there, done that! I too was blessed with high energy, demanding children who never saw the need for sleep! I had to give up on my workouts for a few years: I was in grad school, teaching, taking classes, keeping house and raising kids, and it was just too much. When they were teeny babies, they both refused to lie under their mobile toys and play while I got in a quick workout. That was frustrating. So, I just strapped them into strollers, or put one in her stroller, the other on her trike and we went out walking.
Later, when we moved into family housing and they were older, I could get a quick hour's workout in after school while they were happy to play in their room with toys or outside in the yard. Latterly, as they got older, I worked out in the evenings/night once everyone had been given dinner and they both were settling down to homework or bed.
There just was never a routine. I had to keep adapting to the family timetable, staying flexible to take advantage of physical activity whenever I could cram it in. I still do.
Do what you can. Sometimes sleep/rest is actually more important, otherwise you lose your sanity. The best solution is always if you can get your partner to look after them while you workout. For me, knowing that they were looked after, entertained and happy freed me mentally to be able to focus on me for a while. If my mind was still on them, I couldn't go off and work out. Just couldn't do it. Still can't! And now they are 18 and 21 and their timetable still determines my own. Sigh...
Each woman and her personality and situation is different: find what works for you. And whatever somebody else may think of it: ignore them! Do your thing. Sometimes you have to be selfish too, in order to get your 'me time.'
Clare