Here's my guess. You didn't tolerate Ex-H drug use - and you ended up raising your daughters alone - providing them with reasonable household rules and boundaries for the safety and care of everyone. You've found a forum of parents who have children who believe (much like your youngest daughter) that rules and boundaries are fluid. Ebbing and flowing with the daily tide.
So your daughter, who didn't respect the rules and boundaries, questioned your authority to #1 - Make them (I mean, really, who ARE you? ..says difficult child)
#2 - Enforce them (Just try and make me....says difficult child)
#3 - Give the consequences (Oh please, just one more chance, I PROMISE!...says difficult child)
Anything sound familiar? difficult child's are great at throwing guilt at parents. Whining, crying, begging, pleading, promising, "you would if you loved me" phrases....
We love our children, and we want the best for them. We hurt when they hurt, and it is in our nature to eradicate threats to our children. In my case, my difficult child's biggest threat to her safety and security is herself. It's hard to eradicate your own child.
Detaching takes some time, some practice, some tears, some more tears, venting to friends, some prayer.... It isn't easy.
You're among friends here...come cry, vent, shed some tears.