How do you know when it's time to give up on your marriage?

 My husband has ADHD, we've been married for 19 years.  We didn't know he had ADHD until we were in our late 20's and we're now 42. I have stayed with him although he has cheated on me three times (one being with my now sister in law).   He has not been able to keep a job more than a year for over 10 years and because of this we are now in bankruptcy.  I've kept us in this house as long as I can, I've exhausted all of my savings and 401k.  I've given up on what was once our beautiful house.   I tried for 11 years to keep it clean and beautiful as a source of pride for our family.  We have two children, 13 and 8 who ar a constant challenge to keep up with and I get no consistent parenting teamwork from my husband when trying to lead by example.   Two years ago was the final straw.  My husband was unemployed and supposed to be looking for a job, while I was working a full time job, cooking, cleaning, managing our finances and the children's activities.   I discovered my husband having an online affair with a woman and discussing plans to meet her when she came in town for her daughter's gymnastics appointments.  At that point I had my fill and told him I want a divorce.  He talked me into trying to work things out and my condition was that he get therapy, as we had already been to marriage counseling that had not changed anything.  During this time i I basically had a nervous breakdown.  I constantly shake now and suffer frim severe depression. Two years later our house looks like a disaster zone, I'm so depressed I can't get out of bed some days, he still has not gone to counseling, has had two jobs and I feel so trapped and alone.  Even if I do get a divorce I don't know if I can get an apartment because our credit is so bad.  I have thought of suicide so many times but will not do that to my children.  I have lost every hope and dream of what I wanted from my life and he has broken every promise and vow  he made to me before and after our marriage.  I feel like I'm shell of the person I once was and the mother and woman I wanted to be. I love him so much, but sometimes love isn't enough and it is now affecting our children's lives.  I don't know what to do!!