I don't know if I should just give up

I have been married to my ADHD husband for 5 years, and we have no children.  More and more lately I have been fantasizing about just asking for a divorce and throwing in the towel.  The main reason I haven't yet is because I'm terrified of the whole "grass is always greener" situation where I will regret doing this (as divorce should be an absolute last resort).

My husband and I have fallen into a sort of parent-child relationship.  I do not like the person I become when I am around him.  In the early years of our marriage we fought constantly.  After he got on a good balance of medication things got better and the fighting stopped.  However, due to the fact that we married young (I was 22), I feel like I am a completely different person than when we married.  I used to be shy and co-dependent and introverted.  In the last few years I have taken up new interests that have led me to such a happy place where I am exactly the person I have always wanted to be, and having a spouse I feel like I have to "take care of" is exhausting me and making me fall into a depressed state.  Any time we have been in a period of not fighting it's due to the fact that I have been detaching emotionally from him to prevent myself from feeling pain.

I've reacted by distracting myself with activities with my friends outside of the house.  My husband does not even seem to notice when I am gone anymore.  He is constantly on his computer every minute of every hour he is home.  I have become lonely in my own house and every fiber of my being is craving freedom.  I would rather be lonely by myself than lonely while being stuck to someone else.

I feel chained up, and I am really confused about what to do.  I feel like if I could just throw divorce out of my mind as an option for a while then I could give it one last effort to really work things out, but I am so preoccupied with it that I can't focus on making things better, I can only fantasize about escaping.

My husband is fully aware of his ADHD, but he seems to use it more as a scapegoat for the way he acts rather than taking any kind of responsibility to help our relationship.  I gave up over a year ago and have just been living an existence where I am merely coping with this life I have chosen.

How do I know when it is truly time to throw in the towel?  Is there even any hope for me to change my mentality to give this another shot or is there even any point?