Judith,
I can exactly understand your word of being lost. Being married these many years in a situation like this, you have self destroyed yourself for a very long time. But its never too late. You have to start to understand yourself and the reality surrounding you.
Counselling and therapists can help you and guide you. But its you, who have to take response about your life as well as your well being.
Saying is lot easier than being done. I myself came to this forum when i felt like i'm lost. Its not at all easy to get out of what a messed up state we are in. But before trying to do anything, you have to first start thinking who you are, what you want to be, what type of life you want to give your kids.
Keep asking all such type of questions to yourself until you find an answer what you really want to do with your life. Once you realize that, you have to keep moving on with whatever it takes for betterment of your life.
Start from seeking a good therapist help.
And above all, you have to understand whatever emotions you are going through is completely normal. Whether it is anger or tears or how you feel you are in a dark. You don't have to be a saint and accept yourself that you are a normal human being. Don't lose trust in God and never lose hope on yourself.

I have to say that there is a cultural difference that is very difficult to overcome. I married a Hindu which do consider better then having been a Muslim and life has not been as difficult for me as yours has been, but there are similarities. Just need to focus your internal strength and leave.