My exBPD partner is not the father of my children
The father of my kids is actually being very supportive and helping me get thru this by listening to me and providing extra care with the kids
I am grateful to him for this
This is good. You can be there for your children. If you allow the last 3 years to guide you, you're going to find you are running up against a brick wall. If you are forward thinking, which you can be, take each day as one where you can show them that life is different now, and you ARE present.
People are resilient, and especially your kids who adore you. They have some idea of what's going on. Be honest, and be the parent you want to be. Baby steps... .