Hi Sharon,
Let's put aside the fact that you are married, for a moment, and consider a possible relationship with your boss. Because even if you were unmarried and free to pursue him, you would end up disappointed.
He and his family will not accept the fact that you are Catholic and ten years older. Period. If he is a good, practicing Muslim, he will never consider marrying outside his faith. You are wasting your time, energy and emotions.
The thing is you "fell in love" with him because you have a close working relationship where he needs and depends upon you. You mistook that for love. It isn't.
Now, let's remember that you are a married woman. If he is a good, practicing Muslim, he would never consider committing adultery. As a Catholic, you shouldn't be considering adultery either. In heart, mind or body. At least as a Catholic, you can go to confession and make amends.
Let's consider your husband of 12 years. You said you did not doubt that you loved each other until now. You feel that way only because you've become infatuated by your boss. Once you come out of the haze that makes you believe you and your boss can have a relationship, you will remember that you love your husband.
Your husband has a 12 year track record with you. Be careful not to imagine that your boss is better. He is a man with his own imperfections. If you spent 12 years with your boss, you'd see them.
My advice to you is to see your work relationship for what it is: a business relationship. Otherwise, you could end up risking your job and not just your marriage.
In fact, if it were possible, I would quit your job. Your husband's ominous comments could land you three in a horrible situation.