Is it worth the effort to stay? Or better to cut and run?

Hello. I am new to this site and like others, am finding myself realizing that I am not alone. THANK YOU! For the past year I have felt like I was living in this weird twilight zone or alternate reality and feeling crazy.

So..Here's my situation. I've been married for 4 years to a man that I have been in love with for 18 years. I am 39, he is 42. We met when we were both out of college (undergrad) and into travel and fun. I went back to grad school, he travelled the world (literally) to surf and explore. I always thought he was the coolest, smartest, funniest person alive. We kept in touch over the years but I was unable to really commit as he didn't have a "real job" or a "plan." He then pursued teaching (went back to school for a teaching credential)--lasted 3+years, fly fishing guide-3+ years, construction estimating- 3+years, then institutional sales for investment bank 1+yr. After many on again, off again times of being reunited, we finally got married.  I figured..I loved him, he is a good person, I want kids, and I'm not getting any younger.

Fast forward 4 years. 2 kids (3yr old and 5 mon old) and a mortgage for a house in a pricey community in Northern California later. (I should also mention the financial crisis/recession too.) My husband lost his job in March 2009 and has been doing alot of hanging around, some manual labor, and now is a waiter 3-4 days/week at a restaurant down the street. I am the sole breadwinner and have been for over a year. I own a small business and am fortunate that I have been able to pay our bills. My husband has essentially "checked out" and does not seem to think that he needs to help financially. During my pregnancy when I tried to talk to him about getting a job and feeling worried about paying the mortgage, his 3 solutions were 1) I should work more, 2) I should use my 401K, or 3) his mother would help us. I cannot begin to explain how mad this made me much this made me feel that there was something very WRONG with him. What able-bodied, intelligent, well-educated man would say that to a PREGNANT wife?

This past year has been the worst year of my life. I finally convinced him to go to therapy (which I am paying for.) He has connected with his therapist and the therapist mentioned  2 weeks ago that my husband may have ADD and poor executive functioning. When I first heard that, I could not believe it but after reading about it and reading the info on this site, I think it is right on track.

My questions:

1. At this point, I feel so over it. I do not respect him, I am not attracted to him (how can I be attracted to someone who feels more like a 15yr old). Has anyone had a shift in regaining respect for their husband? 

2. My husband has been referred to a psychiatrist for meds. I am all for this. Do meds help someone with motivation as well as attention? Does motivation follow when attention improves? Or are these separate issues?

3. I am all for recovery and healing and of course I wish the best for him. But is it even worth it? I am so over being the "mommy/bitch/nag" to him. I am a "grown-up" with 2 little children to take care of and want a partner to talk to, have fun with, share responsibilities, and navigate life with. Part of me feels that life is just too short to be dealing with another person's overwhelming BS--it is so exhausting. Thoughts?

Thank you very much!