People always find the time for the things they want to do, barring illness or huge life issues (or kids...kids take a lot of time and effort, which is why I never had any...). It's okay to not want to keep a consistent schedule, but then don't feel terrible about it. Embrace the idea that uploading irregularly works better for your life and your current interest in YouTube and adjust your expectations accordingly.
That sounds snarky, but I'm really not trying to be. There are a lot of things to do that are easier to keep up with and more rewarding more quickly than YouTube, but it's also a perfectly okay platform on which to just add content when you want to. There's no rule stating you have to upload on a consistent schedule; it's just better for finding an audience and growing a subscriber base.
If you miss an upload in your schedule, get right back on the schedule. Then don't miss an upload again. Pre-recording and using the scheduling option can help. Using the mobile uploader on your phone to do a quick, "Hi, I'm still alive and will be back" to let your audience know on the expected day is easy enough.
It seems that, with scheduling questions, people want to know how to upload regularly when they don't really want to upload regularly, which...it's hard, really. As Yoda says, "Do or do not. There is no try."