Landofconfusion.... you are not alone.. I too have the same feelings.. we've been married 8 yrs.. I have fallin for someone.. and they too are also married.. and we know that nothing could ever happen... and wont happen.. but I to cant seem to get this person outta my head..
I love my husband very much but in the same I would love to see why my heart goes elsewhere.. but in the same fact i dont want to ruin what I have. I am also trying to work on My marriage.. only difference is I am not avoiding whom.. I have fell for. which in reading your post I think I must.. to move on with my marriage.
So you are not alone.. at all.. good luck and stay strong..