Where to draw the line?

My husband and I have been separated for 5 months.  There were a few reasons for the separation (which I will briefly mention later) but since the separation I've tried to move on with my life.  My husband pushed me away through his actions and words.  My question to other married couples dealing with an ADHD spouse is:

1) am I abandoning my husband or not trying hard enough if I move on?

2) How do you differentiate bw what's ADHD and what's abuse?  (When I say abuse I mean, "punching bag" for anything that goes wrong whether is work, driving related, losing something.  He's abandoned me/left me stranded with no way to get home, he's yelled, screamed, threatened to leave me, threatened to hit me, name-called, etc)

3) what's the percentage that we'll actually make it if I do decide to stay or am I prolonging the inevitable?  Should I view divorce as an opportunity to better my life?

4) will children make our marriage worse? and will he be able to control himself in front of the kids? and is it highly likely he will act out on the kids the same way he does with me?

As you can see, I'm searching for answers and every day I reflect upon my situation and I'm frankly lost.  What follows is depression.  I love love love my husband but he has untreated ADHD.  It's been 5 years of him trying/wantiing to change but also 5 years of constant anger, anxiety, depression, walking on eggshells, fighting (over god knows what), name-calling, impulsivity.  I need to have the same love for myself and be selfish for once so that's my dilemma.  I want to make sure I have a good future like I wanted and deserved.  If I could do it with him I would but my experience with him has been a very difficult one and has negatively impacted my emotional/mental state...not to mention ruin my self confidence.

I'm very confused and its one big pile of mush. My husband has said he hated me and wanted me to find someone that will love me.  Now that he realized he was losing me treatment became his priority and he loves me and can't live without me.  This roller coaster is so unnecessary and I need peace.  I've been a punching bag for 5 years and I'm terrified of giving him a chance and this blowing up in my face and ruining me.  I can't handle being hurt anymore...I'm at a breaking point. 

Do people with ADHD have 2 sides...cruel/heartless/angry....then...nice/gentle/caring?  Could there be something else wrong with him and doctors aren't diagnosing him?  Is he narcissistic or does he have BPD?

I don't want to give up on my marriage but I also can't live life and be abused whether its a disease, genetics or whatever you want to label it.  I would love to hear other opinions.  This is the only place where I can find support.  Thanks in advance for your time.