I am married, as well, and ,yes, it has affected my marriage.  I have heartbreakingly fallen in love with TGirls over the years, become friends with some, and enjoyed pure, physical hot sex with others.  I have stayed married, despite my "obsession", because I do love my wife, because of the financial ruin that would accompany divorce, and because my kids lives would be negatively impacted were I to leave.  My wife knows of my desires and some of my past activities, but I hide my ongoing activities from her. I wish I knew of my sexual desires earlier in life.  It is tough to be just a paying visitor in a place you'd like to live.  
I think we are a breed apart, just as TGirls are.  Unique and with our own individual stories to sort out.  I, personally, have used therapy and self-reflection to help me sort things out for my own edification.  It has helped me to a level of self-awareness and self-acceptance that I never could have achieved on my own.  It hasn't quelled my desire, but that is not a goal of mine.  I only want to understand who I am and how I became the person I am.  That aside, I don't think therapy is the answer for everyone. Like I said, we are all different despite the "desire" we share.

Life sure does take some unexpected turns, doesn't it?