I am so sorry to hear this. I cannot even say that I know what you are going through, because I can't. I cannot even imagine what it will be like.
You have the right to reevaluate your commitment to him. This is not the man you married. You married a heterosexual man that promised to love you, and just you. What you have now is a cheating husband, he is not hetrosexual and he put your health at risk without any regards for your safety.
That does not mean you have to leave him, or that you have to stay with him. Only you can make that decision. You have to figure out if you can ever trust him again, and if you think he really want to be with only you. If you need help, find a therapist, either for you alone, or for you as a couple. You deserve to get professional help.
Please have an STD screening done as soon as possible.
Best of luck with your decision!