what you did was wrong! you shouldve ended the first relationship if you wanted to persue another.
now, you have to be honest with yourself. in this situation someone is going to get hurt. but you cant lead anyone one, things do come back on you. the only way you can make it right is getting your marriage annulled, and getting back with your ex. only do this if you feel as though it's right.
but if you think that you want to give your marriage a change then you have to let go of your ex. but don't play in the middle with these two men, b/c it's not right.
if you get back with your ex things will change, he might have trust issues with you.