I applaud you for somehow managing to have primary custody of your toddler. Clearly your professionals saw that her poor behaviors rose to a level where they became
actionable. Too many fathers face a system where Mother gets default preference in so many ways. In my case, I started out as alternate weekend dad but did manage after nearly six years (!) to become Legal Guardian.
The take-away from the above is to make your goal to keep as much parenting and custodial responsibility as possible. This is not a time to hope being overly fair, nice and generous in sharing parenting will mollify her, much less fix her. Sadly, if she detects that then her perception, already skewed, will be that your
boundaries are weak and an invitation for her to sabotage and overwhelm them. So the advice is to "not let your eye feel sorry" for her predicament. She's an adult. She is responsible for her actions and consequences. The reality is that you can't fix her. You can't even make her get better in therapy. (Odds are she will
never become the mother you want her to be.) Yes, you can support that she gets therapy but you have no assurance that she will apply it long term in her life. As
worriedStepmom emphasized...
You may have better luck...but only if your ex is open to feedback from you AND willing to make changes.
Please read
zachira's post often, the comments are perhaps stronger than you had expected but they are totally practical
and essential. (The fact that courts are generally reluctant to grant full custody, at least at first, does not invalidate your need to consistently advocate for your child's best interests, both short term and long term.)
Others will post here too with additional thoughts and perspectives. We have an immense wealth of hard-won experience and strategies. We've seen what usually works and what usually doesn't work.
As difficult as it has been for you, you have also been exceedingly fortunate thus far:
You are you child's Primary Parent. Few fathers here manage to get a head start as good as yours. Never ever think about 'gifting' parental authority back to your ex. Why? Because either you will have a hard time getting it back, or your child will become a method she uses to control and punish you.
Though your impulse will be to demonstrate how nice and sharing you are, understand that the professionals don't care whether either parent is overly fair, overly nice or overly giving, as though gaining points means something. Just be a good and protective dad. There's a saying here, "The parent behaving poorly seldom gets consequences and the parent behaving well seldom gets credit." If she gets consequences, good, but you can't count on always getting credit for your proper care of your child.