inpain - What to do about his access to the children? This depends on a couple of things. The most important is your motivation for changing anything.
I personally never really interfere when H wants so spend time with the kids. He used to spend so much more time with them than he does now. So I tend to just let him visit on the rare occasions they cross his mind - but my kids are older.
Is he interfering with bedtimes? Is he getting in the way? Your D is definitely suffering from his not being there as often. I don't know the answer for you, but I would advise that you make sure to proceed with caution, check your motivation, and make sure what you're putting in place is best for the children.
A schedule is great for establishing order and routine. On the other hand, if you have a WAS who misses his visits on scheduled days, and doesn't try to make it up - the kids ultimately are the ones hurt.
I'll support you either way. You've got to do what's best for you and the children.