How do I know if I can fix this?

I can relate indeed... I have 2 daughters and I my husband is my third child. I know how frustrating it can be to be sooo utterly annoyed with his every move. It has devastated our relationship. I have done my ultimate best to explain to him how I feel and where I am coming from. He does not understand, but in the midst of wanting to make things work, he has left at my request so that I can discover on my own if this IS what I want. I truly believe that it is. I have pretty much set his agenda.. he will pick up our children on days that I have other obligations and I am leaving the weekend decision up to him if he wants to come here and me leave or if he will take them elsewhere...  I told him that I will go to counseling with him. He is going in hopes of mending things, maybe (in my head), and right now, I am going to help him understand my reasoning... he does not know that, and that's ok. I think this way we can both have time to thoroughly think things thru and work together.. hope this helps.

No one can answer that question for you except yourself.  It sounds like to me you have already made a decision in you head.  I am sorry that you have gotten to this point in your marriage.

I know that it can be a very devastating thing to deal with when something "dies" so to speak.

Marriage counselling may fix the problem.  You have to decide whether or not it is important enough to go after in the end.

Not much advice from me here, just my two cents worth
take care