When is enough, enough?

So, I had a long week last week.  At work, we had a week long review which meant long hours.  After I get home, at 9pm, my husband tells me that he may be getting fired.  And he is SHOCKED!  *sigh*  Let me start off with saying, he works for his parents business.  So, he was performing so poorly for such a long time, even his father is having a hard time employing him (though his father, or any family member, is not his direct manager).  He has been performing poorly for about 2 years, and we've talked about it, I've warned him that he wasn't following through on his projects and that he needs to work harder.  Each time, he said "ok" and for a week work harder and then drop it.  So, the fact that he was *shocked* that he was being considered for termination completely blew my mind.  And then, he spent the next 2 hours complaining about how his manager is out to get him and in general blaming others and being irrational and spiteful (a lot like our arguments).  It took me 2 hours beyond that to make him understand that "you can't get fired if you don't deserve it."  And of course, we went through the same thing of "ok, I'll do better, I'll work harder, I'll do it this time."  I hate to say it, but my expectations are not very high.  Oh, and his father did save his job, again.  There's something about relying on my in laws' for my financial situation that bothers me.

So, when is enough, enough?  He's started meds, but refuses therapy.  I try to suggest cognitive therapy, and he says "maybe" but I know if I want him to go, I need to research it, I need to make the appointment, and I need to remind him to go.  Would it even do any good if he won't do it on his own?  The fact that can't he hold down a job unless it's with his parents truly worries me.  What if I can't work for whatever reason?  He's really not trying to manage his ADHD at all.  We don't have any children and I know I'm not dependent on him in any way.  It's like we're tolerated roommates.  I miss having a real relationship.  I've even started dreaming about it...just having a companion that loves me.

I want to be able to say I've done everything I could.  And I feel like I'm getting there.  I want to stay married...but not just for the sake of being married.  And I don't know where that line is.  I just don't know what to do anymore.  I've tried talking, but it goes in one ear, out the other.  I've tried couples counseling.  Is there something I haven't tried?