OK, now that I've calmed down a little here is my feedback. But I have to tell you, the entire time I was reading your post and for at least three minutes afterward, my ENTIRE body was covered in goose bumps. I felt like I was watching the events you described unfolding before my eyes. I felt like I was watching a horror film.
I am having a really hard time answering your post. I want so badly to tell you what to do. I think your story is a HUGE trigger for me. I want to tell you things to convince you to get away from this monster as quickly as you possibly can.
I think you need to go to Al-Anon. Here is a locator:
How to find a meeting in the US/Canada/Puerto Rico. Please go.
Here I offer my own perspective. Please take what you like and leave the rest.
CHEATING IS GROUNDS FOR TERMINATION OF THE RELATIONSHIP - PERIOD
This is one of your obviously very strong morals/values. Always remain true to your morals and values. When we do not remain true to them, we lose our way. We inherit someone else's false compass. Follow YOUR OWN compass, not his or anyone else's. Look for other ways you may have ignored your own compass and make note of those things and what convinced you to ignore your morals and values. Notice how doing so snowballs.
I met what I thought was "a man sent to me by God"
I have done this too. I have placed many men on a pedestal and thought that God must have sent him to me. Now that I have done this almost ten times, I finally have learned that God does not send men to me. I CHOOSE the men I get involved with. I understand that I have the tendency to make the man I am involved with my Higher Power (my God). No, I don't get on my knees and bow down and chant or say prayers to him, but I give my own personal power over to him and follow him. I have learned that I have to follow God as my Higher Power, not a man. This does not mean I have to belong to any established religion. It also means that I must have a strong sense of what I need for my life now and in the future. It means that I have a very strong idea of where I want to be 5, 10, 20, and even 30 years from now. And I have to be 100% responsible for my own wants, dreams and desires. It means I cannot hand responsibility for those things over to someone else. My life is between me and my Higher Power.