How much is too much?

I have been reading this forum and decided it was time for me to post...

I am a non-ADHD man living with my girlfriend of nearly 6 years who has ADHD. She was diagnosed while in high school and has tried different medicines and approaches.

She is ready to get married (and rightly so). I want to be married to her and have kids, but her ADHD symptoms drive me crazy. Our entire relationship, she has been habitually late, lacked motivation for the most part, neglected responsibility (including household chores, and any financial responsibility). She has worked a few jobs, but most have been part time, low paying jobs like babysitting. I assume full financial responsibility even though we are not married. I also have assumed most of the household tasks like cleaning and cooking. She thinks I do this because I am stubborn, but I see it more because I know cleaning and cooking and paying bills has to get done.

Over the years I have told her that these things really bother me. I may not have been vocal enough about it, but I did tell her. Within the past year, I thought the problem may not be with her, but with the way I handle my frustration. So I went to therapy and was diagnosed with anxiety disorder. I have been working on keeping my thoughts and frustrations inline. I have become more vocal about my frustrations with her while also becoming more distant. She has made attempts to work on her ADHD symptoms, but they still happen. She was just recently very late when we were leaving with some friends to go out of town. I felt like that was the moment things changed. I realized that I could no longer handle the frustration caused by these symptoms.

I don't know what to do now. She is waiting on me to give her an answer about whether or not I am fully committed to her and will marry her soon, or if I feel like these are things I cannot overcome. I feel horrible to think that I could deeply love and care about her, yet be unwilling to accept her faults and move forward with marriage. I'm afraid that if we get married and the ADHD issues persist (which she says they will), then my frustration will grow and grow until I breakdown.

My therapist has helped me a lot with this situation. Any advice would be great and I appreciate all the good advice in this forum.