Don't get me wrong, we love our kids and I would not change anything. But the difference was substantial. With two toddlers, one parent per child, that works.
The third was a "surprise". We didn't think it would make much of a difference, but boy were we wrong! We have very little time to ourselves, but that's because we have two toddlers and a baby. They're very demanding and constantly need attention.
The only way we make it work is childcare during the day, which is very expensive for two, but when we have all three, it's carnage. When they're all finally asleep around 7 pm, then it's the baby's needs which kick in. Sometimes the toddlers will wake up while trying to get the baby down.
By the time everyone is finally asleep it's about 9:30 pm - 10pm, which doesn't leave much time for us.
It's very depressing, but it's the choice we made so we have to deal with it.