How heritable is ADD? Thinking about children...

New to this. Strongly suspect that my husband has ADD or an LD.  Strongly suspect this, based on his behaviour and the behaviour of his relatives. 

I feel so scared. Feel so sorry for DH.  I know he is suffering.  I love him dearly, he is the love of my life.  He is so loving. But many broken promises leave me feeling betrayed. So so scared that if we were to have children, I would have to watch them struggle with the same would just tear me apart.)  Also scared that I may never have any children, if I end my marriage.  Ashamed. Guilty.

I am the sole provider, the primary maid, the mother, the teacher, the HR counselor, the cook, the butler, the enabler.  Our marriage has just begun. His helplessness worsened over the course of our courtship, and hit me in the face after we married. My therapist suggested divorce, but how can I? DH has no control over this.  Nevertheless, I am considering it.  Have even gotten some legal advice. 

If you could go back in time, would you still marry your ADD spouse?  What do I do now?  Do I leave?