Many people see 'original sin' as a depressing doctrine. I see it as refreshingly realistic and liberating.
You don't have to pretend. You don't have to pretend to be perfect: you are flawed. God knows it, and you can be pretty confident that the people around you know it too.
You can be reasonable in your expectations. The people around you are flawed, too. You may ask for perfection, but don't expect it. Not all the time.
Your children are human. They are flawed, just like the rest of us, and always have been. You may have let them down, disappointed and damaged them in all kinds of ways (being less than perfect, it is likely that you did) - but their problems are not all created by you and your inability to protect them from the world. Some of their problems are entirely of their own making. Even without you to let them down, they would still have been flawed.