Since when did it become a requirement to pay for a kid's private school university tuition in full? While my parents helped out where they could (probably $2-$3k a year for the 4 years), i certainly bore the load of my degrees. My parents did what they could, but it doesn't mean they OWED me my education.
And while it may have been tradition to pay for your daughter's wedding in the past, it is by no means a requirement. Plenty of couples pay for their own wedding. We were lucky in that my parents gave about 1/3 of the cost of our wedding, but again, we didn't expect anything from our parents.
I sympathize with the idea that as parents you want to at least help your children out as much as you can, but I don't think it makes you a bad parent if your kids need to take out some loans for school. If anything, knowing how much they would have to borrow may help them to focus realizing they need a good job when they get out of school and also to choose wisely on which school to attend based on financial aid, scholarships, in-state v out-of-state, etc.