i know exactly what you are going through... i'm in the same situation except he's not married... I am dating his cousin/best friend for the past 2 years.. he hate's it but i really love his cousin.. although i constantly think about him... i've thought of just confronting him but that will ruin everything between me and my present boyfriend and that might give him a reason to break us up and plus i might regret it once i get it odd my chest!! .. i like what you said though, you do know when he feels the same way because when he looks at me, ahh, he looks deep within.. but then we just turn our heads awkwardly and act like we never looked at each other.. i met him when i was 15 and he was my first love and i lost my virginity to him.. but he became way too possessive and angry and i moved on... im 21 now but the feelings still remain...
Sometimes it's best to let go of the past and stop wondering about what could have been... he's married, he has a child... your moment has passed sweety.. take a long vacation somewhere tropical with your present boyfriend and see where it takes you. i bet you will learn more about him and who he is in that trip than you ever had in all your time of dating him.. Don't go looking for prince charming, you have to make him :)