Love and ADHd

I have been with the one I love for 2 years. I have plan to marry her but ADHD prevent us from moving forward .I have tried everything to get her to understand that I am here with her for the long run,but nothing I to do seem to gets threw to her and as I sit here typing 4:44 in the morning after a long night of going back and forth,one of many I wonder to myself Is it time for me to move on. How do you leave some one you love when you commit to not only them but to God. Sometimes thing are OK most times seem hopeless. I have empathy for her situation but she uses it as an excuse. The forgetfulness Is the cause for all the arguements and everytime I point out a bad behavior My faults are just pointed back at me.So the Question is how do you watch a loved one  on a road to destruction and they see no problem.She takes the medication and believes it to be a cure.  HOW DO YOU LET GO SOMEONE YOU LOVE!!!