Laurie -
I am sure that you feel like you are walking around with a cloud over your head. I have often felt that way. It would get to the point when I would say to myself, "Okay, what is next?" because I knew something else would go badly. The truth is, though, no matter what sort of pattern we feel we are experiencing, we will get through it. There is nothing that can be thrown at you that you cannot face and will not get through.
Regarding your AH's infidelity, I don't know what to say. To my knowledge, none of my exes cheated on me. I would be hurt if I found out any one of them had, especially my XABF. I hope some others who have been through that experience can offer you some encouragement.
Good luck with everything, and I am sure things will be on the upswing and soon. "The only constant is change."